diff --git a/app/actions.cpp b/app/actions.cpp
index 75e2383b..2faa67b7 100644
--- a/app/actions.cpp
+++ b/app/actions.cpp
@@ -1,49 +1,39 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
-#include "app_utils.hpp"
 #include "actions.hpp"
-#include "exiv2app.hpp"
 
-#include "image.hpp"
-#include "jpgimage.hpp"
-#include "xmpsidecar.hpp"
-#include "types.hpp"
-#include "exif.hpp"
+#include "app_utils.hpp"
+#include "config.h"
 #include "easyaccess.hpp"
+#include "exif.hpp"
+#include "futils.hpp"
+#include "i18n.h"  // NLS support.
+#include "image.hpp"
 #include "iptc.hpp"
-#include "xmp_exiv2.hpp"
 #include "preview.hpp"
-#include "futils.hpp"
-#include "i18n.h"                // NLS support.
+#include "types.hpp"
+#include "xmp_exiv2.hpp"
 
 // + standard includes
+#include <sys/stat.h>   // for stat()
+#include <sys/types.h>  // for stat()
+
 #include <filesystem>
-#include <string>
-#include <iostream>
-#include <iomanip>
 #include <fstream>
-#include <sstream>
-#include <cstring>
-#include <cstdio>
-#include <ctime>
-#include <cmath>
-#include <cassert>
+#include <iomanip>
+#include <iostream>
 #include <mutex>
-#include <stdexcept>
-#include <sys/types.h>                  // for stat()
-#include <sys/stat.h>                   // for stat()
+#include <sstream>
 #ifdef EXV_HAVE_UNISTD_H
-# include <unistd.h>                    // for stat()
+#include <unistd.h>  // for stat()
 #endif
 
 #if defined(_WIN32) || defined(__CYGWIN__)
-# include <sys/utime.h>
 #include <Windows.h>
 #include <fcntl.h>
 #include <io.h>
+#include <sys/utime.h>
 #else
 #include <utime.h>
 #endif
diff --git a/app/actions.hpp b/app/actions.hpp
index 3022c782..28e690f0 100644
--- a/app/actions.hpp
+++ b/app/actions.hpp
@@ -12,7 +12,6 @@
 #define ACTIONS_HPP_
 
 // *****************************************************************************
-// included header files
 #include "exiv2app.hpp"
 #include <unordered_map>
 
diff --git a/app/exiv2.cpp b/app/exiv2.cpp
index 2682342a..310e2f52 100644
--- a/app/exiv2.cpp
+++ b/app/exiv2.cpp
@@ -8,7 +8,6 @@
 #include "exiv2app.hpp"
 
 #include "convert.hpp"
-#include "futils.hpp"
 #include "getopt.hpp"
 #include "i18n.h"  // NLS support.
 #include "xmp_exiv2.hpp"
diff --git a/app/getopt.cpp b/app/getopt.cpp
index 3c76ae27..f949fee0 100644
--- a/app/getopt.cpp
+++ b/app/getopt.cpp
@@ -1,17 +1,12 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include <assert.h>
-#include <errno.h>
-#include <filesystem>
-#include <iostream>
-#include <stdlib.h>
-#include <string.h>
-#include <stdarg.h>
-#include <stdio.h>
-
 #include "getopt.hpp"
 
+#include <cstdio>
+#include <cstring>
+#include <filesystem>
+
 namespace fs = std::filesystem;
 
 namespace Util {
diff --git a/app/getopt.hpp b/app/getopt.hpp
index c6e5be9a..c92416fc 100644
--- a/app/getopt.hpp
+++ b/app/getopt.hpp
@@ -21,8 +21,6 @@
 #ifndef GETOPT_H
 #define GETOPT_H
 
-#include <ctype.h>
-#include <stdio.h>
 #include <string>
 
 namespace Util {
diff --git a/include/exiv2/types.hpp b/include/exiv2/types.hpp
index acb74c95..c8985656 100644
--- a/include/exiv2/types.hpp
+++ b/include/exiv2/types.hpp
@@ -11,10 +11,7 @@
 
 // + standard includes
 #include <algorithm>
-#include <limits>
 #include <sstream>
-#include <string>
-#include <vector>
 
 /*!
   @brief Macro to make calls to member functions through a pointer more readable.
@@ -26,8 +23,6 @@
 #define EXV_CALL_MEMBER_FN(object, ptrToMember) ((object).*(ptrToMember))
 
 // *****************************************************************************
-// forward declarations
-struct tm;
 
 // *****************************************************************************
 // namespace extensions
diff --git a/samples/addmoddel.cpp b/samples/addmoddel.cpp
index b858f7a6..0adb6516 100644
--- a/samples/addmoddel.cpp
+++ b/samples/addmoddel.cpp
@@ -21,8 +21,8 @@
 // Sample program showing how to add, modify and delete Exif metadata.
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
 #include <cassert>
 
 int main(int argc, char* const argv[])
diff --git a/samples/convert-test.cpp b/samples/convert-test.cpp
index 51d1318b..0580ea4d 100644
--- a/samples/convert-test.cpp
+++ b/samples/convert-test.cpp
@@ -21,8 +21,8 @@
 // Conversion test driver - make sure you have a copy of the input file around!
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
 #include <cassert>
 
 int main(int argc, char* const argv[])
diff --git a/samples/exifdata.cpp b/samples/exifdata.cpp
index da235c67..40c4a8b2 100644
--- a/samples/exifdata.cpp
+++ b/samples/exifdata.cpp
@@ -21,8 +21,8 @@
 // Sample program to format exif data in various external formats
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
 #include <cassert>
 #include <string>
 
diff --git a/samples/exifvalue.cpp b/samples/exifvalue.cpp
index 15485aff..b7c221c0 100644
--- a/samples/exifvalue.cpp
+++ b/samples/exifvalue.cpp
@@ -21,10 +21,9 @@
 // Sample program to print value of an exif key in an image
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
 #include <cassert>
-#include <string>
 
 int main(int argc, char* const argv[])
 {
diff --git a/samples/exiv2json.cpp b/samples/exiv2json.cpp
index 47e24356..2e02bf65 100644
--- a/samples/exiv2json.cpp
+++ b/samples/exiv2json.cpp
@@ -21,25 +21,20 @@
 // Sample program to print metadata in JSON format
 
 #include <exiv2/exiv2.hpp>
-#include "Jzon.h"
 
-#include <filesystem>
-#include <iostream>
-#include <iomanip>
+#include <sys/stat.h>
+
 #include <cassert>
-#include <string>
-#include <map>
-#include <vector>
-#include <set>
 #include <cstdlib>
-#include <limits.h>
-#include <sys/types.h>
-#include <sys/stat.h>
+#include <filesystem>
+#include <iostream>
+
+#include "Jzon.h"
 
 #if defined(__MINGW32__) || defined(__MINGW64__)
-# ifndef  __MINGW__
-#  define __MINGW__
-# endif
+#ifndef __MINGW__
+#define __MINGW__
+#endif
 #endif
 
 struct Token {
diff --git a/samples/geotag.cpp b/samples/geotag.cpp
index 8351b91e..7cc0e5b2 100644
--- a/samples/geotag.cpp
+++ b/samples/geotag.cpp
@@ -22,24 +22,17 @@
 // g++ geotag.cpp -o geotag -lexiv2 -lexpat
 
 #include <exiv2/exiv2.hpp>
-
-#include <filesystem>
-#include <iostream>
-#include <iomanip>
-#include <cassert>
-#include <algorithm>
+#include <expat.h>
 
 #include <stdio.h>
-#include <cstdlib>
-#include <time.h>
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <time.h>
 
-#include <expat.h>
-
-#include <vector>
-#include <string>
+#include <algorithm>
+#include <filesystem>
+#include <iostream>
 
 #if defined(__MINGW32__) || defined(__MINGW64__)
 # ifndef  __MINGW__
diff --git a/samples/getopt-test.cpp b/samples/getopt-test.cpp
index 690302a1..4f15dee7 100644
--- a/samples/getopt-test.cpp
+++ b/samples/getopt-test.cpp
@@ -48,8 +48,6 @@
 #include <unistd.h>
 #endif
 #include <iostream>
-#include <iomanip>
-#include <cassert>
 
 #define Safe(x) (x?x:"unknown")
 const char* optstring = ":hVvqfbuktTFa:Y:O:D:r:p:P:d:e:i:c:m:M:l:S:g:K:n:Q:";
diff --git a/samples/iotest.cpp b/samples/iotest.cpp
index 7a7b8a5e..47e4f955 100644
--- a/samples/iotest.cpp
+++ b/samples/iotest.cpp
@@ -20,10 +20,8 @@
 // *****************************************************************************
 // included header files
 #include <exiv2/exiv2.hpp>
-#include <cstdio>                               // for EOF
-#include <cstring>
+
 #include <iostream>
-#include <stdio.h>
 
 using Exiv2::byte;
 using Exiv2::BasicIo;
diff --git a/samples/iptceasy.cpp b/samples/iptceasy.cpp
index 9363f4be..090ccf20 100644
--- a/samples/iptceasy.cpp
+++ b/samples/iptceasy.cpp
@@ -21,9 +21,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
-#include <cassert>
 
 int main(int argc, char* const argv[])
 try {
diff --git a/samples/iptcprint.cpp b/samples/iptcprint.cpp
index a9a02643..1d5b888e 100644
--- a/samples/iptcprint.cpp
+++ b/samples/iptcprint.cpp
@@ -21,9 +21,8 @@
 // Sample program to print the IPTC metadata of an image
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
-#include <cassert>
 
 int main(int argc, char* const argv[])
 try {
diff --git a/samples/iptctest.cpp b/samples/iptctest.cpp
index 50a61f4d..9fb67a53 100644
--- a/samples/iptctest.cpp
+++ b/samples/iptctest.cpp
@@ -19,9 +19,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
-#include <cassert>
 
 using namespace Exiv2;
 
diff --git a/samples/key-test.cpp b/samples/key-test.cpp
index 6922a96d..ef09534c 100644
--- a/samples/key-test.cpp
+++ b/samples/key-test.cpp
@@ -19,9 +19,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <string>
-#include <cstring>
 
 using namespace Exiv2;
 
diff --git a/samples/metacopy.cpp b/samples/metacopy.cpp
index 5c931dda..11c1227a 100644
--- a/samples/metacopy.cpp
+++ b/samples/metacopy.cpp
@@ -19,7 +19,6 @@
  */
 #include <exiv2/exiv2.hpp>
 #include <iostream>
-#include <fstream>
 #include <cassert>
 
 // include local header files which are not part of libexiv2
diff --git a/samples/mmap-test.cpp b/samples/mmap-test.cpp
index ae218431..7e834668 100644
--- a/samples/mmap-test.cpp
+++ b/samples/mmap-test.cpp
@@ -21,8 +21,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <cstring>
 
 using namespace Exiv2;
 
diff --git a/samples/path-test.cpp b/samples/path-test.cpp
index 4f7a8d4a..5212ed8a 100644
--- a/samples/path-test.cpp
+++ b/samples/path-test.cpp
@@ -20,11 +20,10 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <filesystem>
 #include <iostream>
 #include <fstream>
-#include <sstream>
-#include <string>
 
 namespace fs = std::filesystem;
 
diff --git a/samples/prevtest.cpp b/samples/prevtest.cpp
index 29e5b889..e5e07f6f 100644
--- a/samples/prevtest.cpp
+++ b/samples/prevtest.cpp
@@ -21,9 +21,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
-#include <string>
+
 #include <iostream>
-#include <cassert>
 
 int main(int argc, char* const argv[])
 try {
diff --git a/samples/stringto-test.cpp b/samples/stringto-test.cpp
index 703ea81d..41dd82ea 100644
--- a/samples/stringto-test.cpp
+++ b/samples/stringto-test.cpp
@@ -21,8 +21,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <iomanip>
 
 static constexpr const char* testcases[] = {
     // bool
diff --git a/samples/taglist.cpp b/samples/taglist.cpp
index cc73bc0d..661eebb8 100644
--- a/samples/taglist.cpp
+++ b/samples/taglist.cpp
@@ -19,9 +19,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <string>
-#include <sstream>
 
 using namespace Exiv2;
 
diff --git a/samples/write-test.cpp b/samples/write-test.cpp
index f084348d..6194393c 100644
--- a/samples/write-test.cpp
+++ b/samples/write-test.cpp
@@ -19,12 +19,8 @@
  */
 
 #include <exiv2/exiv2.hpp>
+
 #include <iostream>
-#include <sstream>
-#include <iomanip>
-#include <string>
-#include <utility>
-#include <cassert>
 
 // *****************************************************************************
 // local declarations
diff --git a/samples/xmpsample.cpp b/samples/xmpsample.cpp
index 173e9eb6..66fc7fba 100644
--- a/samples/xmpsample.cpp
+++ b/samples/xmpsample.cpp
@@ -22,10 +22,7 @@
 
 #include <exiv2/exiv2.hpp>
 
-#include <string>
 #include <iostream>
-#include <iomanip>
-#include <cassert>
 #include <cmath>
 
 bool isEqual(float a, float b)
diff --git a/src/orfimage.cpp b/src/orfimage.cpp
index 640335e7..352f27c3 100644
--- a/src/orfimage.cpp
+++ b/src/orfimage.cpp
@@ -1,23 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "orfimage.hpp"
-#include "orfimage_int.hpp"
-#include "tiffimage.hpp"
-#include "tiffcomposite_int.hpp"
-#include "tiffimage_int.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
 #include "error.hpp"
 #include "futils.hpp"
-
-// + standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
+#include "image.hpp"
+#include "orfimage_int.hpp"
+#include "tiffcomposite_int.hpp"
+#include "tiffimage.hpp"
+#include "tiffimage_int.hpp"
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/pngimage.cpp b/src/pngimage.cpp
index 39946f0f..6a0b9516 100644
--- a/src/pngimage.cpp
+++ b/src/pngimage.cpp
@@ -3,28 +3,21 @@
 // included header files
 #include "config.h"
 
-#ifdef   EXV_HAVE_LIBZ
-#include "pngchunk_int.hpp"
-#include "pngimage.hpp"
-#include "jpgimage.hpp"
-#include "tiffimage.hpp"
-#include "image.hpp"
-#include "image_int.hpp"
+#ifdef EXV_HAVE_LIBZ
+#include <zlib.h>  // To uncompress IccProfiles
+
 #include "basicio.hpp"
-#include "error.hpp"
 #include "enforce.hpp"
+#include "error.hpp"
 #include "futils.hpp"
+#include "image.hpp"
+#include "image_int.hpp"
+#include "jpgimage.hpp"
+#include "pngchunk_int.hpp"
+#include "pngimage.hpp"
+#include "tiffimage.hpp"
 #include "types.hpp"
 
-// + standard includes
-#include <algorithm>
-#include <array>
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
-
-#include <zlib.h>     // To uncompress IccProfiles
 // Signature from front of PNG file
 const unsigned char pngSignature[8] = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
 
diff --git a/src/preview.cpp b/src/preview.cpp
index e885960c..d5e846df 100644
--- a/src/preview.cpp
+++ b/src/preview.cpp
@@ -1,25 +1,19 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
-#include <algorithm>
-#include <array>
-#include <climits>
-#include <string>
-
 #include "preview.hpp"
-#include "futils.hpp"
-#include "enforce.hpp"
-#include "safe_op.hpp"
 
+#include "config.h"
+#include "enforce.hpp"
+#include "futils.hpp"
 #include "image.hpp"
-#include "cr2image.hpp"
 #include "jpgimage.hpp"
+#include "safe_op.hpp"
 #include "tiffimage.hpp"
 #include "tiffimage_int.hpp"
 
-// *****************************************************************************
+#include <climits>
+
 namespace {
 
     using namespace Exiv2;
diff --git a/src/properties.cpp b/src/properties.cpp
index 6cf00671..e0972fca 100644
--- a/src/properties.cpp
+++ b/src/properties.cpp
@@ -2,22 +2,15 @@
 
 // included header files
 #include "properties.hpp"
-#include "tags_int.hpp"
+
 #include "error.hpp"
+#include "i18n.h"  // NLS support.
+#include "metadatum.hpp"
+#include "tags_int.hpp"
 #include "types.hpp"
 #include "value.hpp"
-#include "metadatum.hpp"
-#include "i18n.h"                // NLS support.
 #include "xmp_exiv2.hpp"
 
-#include <iostream>
-#include <iomanip>
-#include <sstream>
-#include <cstring>
-#include <cstdlib>
-#include <cctype>
-
-// *****************************************************************************
 namespace {
 
     //! Struct used in the lookup table for pretty print functions
diff --git a/src/psdimage.cpp b/src/psdimage.cpp
index de491f95..75435dc6 100644
--- a/src/psdimage.cpp
+++ b/src/psdimage.cpp
@@ -1,25 +1,15 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "psdimage.hpp"
-#include "jpgimage.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
+#include "enforce.hpp"
 #include "error.hpp"
 #include "futils.hpp"
-
-#include "safe_op.hpp"
-#include "enforce.hpp"
-
-// + standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <iomanip>
-#include <cassert>
-#include <memory>
+#include "image.hpp"
+#include "jpgimage.hpp"
 
 // Todo: Consolidate with existing code in struct Photoshop (jpgimage.hpp):
 //       Extend this helper to a proper class with all required functionality,
diff --git a/src/rafimage.cpp b/src/rafimage.cpp
index 75e7920f..5e883f99 100644
--- a/src/rafimage.cpp
+++ b/src/rafimage.cpp
@@ -1,23 +1,17 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "rafimage.hpp"
-#include "tiffimage.hpp"
-#include "image_int.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
+#include "enforce.hpp"
 #include "error.hpp"
 #include "futils.hpp"
-#include "enforce.hpp"
+#include "image.hpp"
+#include "image_int.hpp"
 #include "safe_op.hpp"
-
-// +standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <cassert>
+#include "tiffimage.hpp"
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/rw2image.cpp b/src/rw2image.cpp
index 47be7da4..6d4605a6 100644
--- a/src/rw2image.cpp
+++ b/src/rw2image.cpp
@@ -1,20 +1,20 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "rw2image.hpp"
+
+#include "config.h"
+#include "error.hpp"
+#include "futils.hpp"
+#include "image.hpp"
+#include "preview.hpp"
 #include "rw2image_int.hpp"
 #include "tiffcomposite_int.hpp"
 #include "tiffimage_int.hpp"
-#include "image.hpp"
-#include "preview.hpp"
-#include "error.hpp"
-#include "futils.hpp"
 
 // + standard includes
 #ifdef EXIV2_DEBUG_MESSAGES
-# include <iostream>
+#include <iostream>
 #endif
 
 // *****************************************************************************
diff --git a/src/tags.cpp b/src/tags.cpp
index 8badc90f..106bc2af 100644
--- a/src/tags.cpp
+++ b/src/tags.cpp
@@ -1,35 +1,15 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "types.hpp"
 #include "tags.hpp"
-#include "tags_int.hpp"
-#include "error.hpp"
-#include "futils.hpp"
-#include "value.hpp"
-#include "convert.hpp"
-#include "i18n.h"                // NLS support.
 
 #include "canonmn_int.hpp"
 #include "casiomn_int.hpp"
-#include "fujimn_int.hpp"
-#include "minoltamn_int.hpp"
-#include "nikonmn_int.hpp"
-#include "olympusmn_int.hpp"
-#include "panasonicmn_int.hpp"
-#include "pentaxmn_int.hpp"
-#include "samsungmn_int.hpp"
-#include "sigmamn_int.hpp"
-#include "sonymn_int.hpp"
-
-#include <iostream>
-#include <iomanip>
-#include <sstream>
-#include <utility>
-#include <cstdlib>
-#include <cassert>
-#include <cmath>
-#include <cstring>
+#include "convert.hpp"
+#include "error.hpp"
+#include "i18n.h"  // NLS support.
+#include "tags_int.hpp"
+#include "types.hpp"
 
 // *****************************************************************************
 // class member definitions
diff --git a/src/tgaimage.cpp b/src/tgaimage.cpp
index ee1705f1..c6115921 100644
--- a/src/tgaimage.cpp
+++ b/src/tgaimage.cpp
@@ -1,18 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "tgaimage.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
 #include "error.hpp"
 #include "futils.hpp"
-
-// + standard includes
-#include <string>
-#include <cstring>
-#include <iostream>
+#include "image.hpp"
 
 // *****************************************************************************
 // class member definitions
@@ -21,7 +16,7 @@ namespace Exiv2 {
     TgaImage::TgaImage(BasicIo::UniquePtr io)
         : Image(ImageType::tga, mdNone, std::move(io))
     {
-    } // TgaImage::TgaImage
+    }
 
     std::string TgaImage::mimeType() const
     {
diff --git a/src/tiffimage.cpp b/src/tiffimage.cpp
index f11e528e..20d9a06b 100644
--- a/src/tiffimage.cpp
+++ b/src/tiffimage.cpp
@@ -1,29 +1,16 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
 // included header files
-#include "config.h"
-
 #include "tiffimage.hpp"
-#include "tiffimage_int.hpp"
-#include "tiffcomposite_int.hpp"
-#include "tiffvisitor_int.hpp"
-#include "orfimage.hpp"
-#include "makernote_int.hpp"
-#include "nikonmn_int.hpp"
-#include "image.hpp"
-#include "image_int.hpp"
+
+#include "basicio.hpp"
+#include "config.h"
 #include "error.hpp"
 #include "futils.hpp"
+#include "image.hpp"
+#include "tiffcomposite_int.hpp"
+#include "tiffimage_int.hpp"
 #include "types.hpp"
-#include "basicio.hpp"
-#include "i18n.h"                // NLS support.
-
-// + standard includes
-#include <string>
-#include <iostream>
-#include <iomanip>
-#include <cassert>
-#include <cstdarg>
 
 /* --------------------------------------------------------------------------
 
diff --git a/src/types.cpp b/src/types.cpp
index 1dd66936..5b955807 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -2,26 +2,21 @@
 
 // included header files
 #include "types.hpp"
+
 #include "enforce.hpp"
 #include "futils.hpp"
 #include "i18n.h"  // for _exvGettext
 #include "safe_op.hpp"
 
 // + standard includes
-#include <string>
-#include <iostream>
-#include <iomanip>
-#include <sstream>
-#include <utility>
+#include <cassert>
 #include <cctype>
 #include <climits>
-#include <ctime>
-#include <cstdio>
-#include <cstdlib>
-#include <cassert>
-#include <cstring>
 #include <cmath>
-#include <math.h>
+#include <cstring>
+#include <iomanip>
+#include <sstream>
+#include <utility>
 
 // *****************************************************************************
 namespace {
diff --git a/src/value.cpp b/src/value.cpp
index cf61b351..fa7c42a4 100644
--- a/src/value.cpp
+++ b/src/value.cpp
@@ -2,21 +2,14 @@
 
 // included header files
 #include "value.hpp"
-#include "types.hpp"
+
+#include "convert.hpp"
 #include "enforce.hpp"
 #include "error.hpp"
-#include "convert.hpp"
+#include "types.hpp"
 
 // + standard includes
-#include <ctype.h>
-
-#include <cassert>
-#include <cstdarg>
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
-#include <ctime>
-#include <iomanip>
+
 #include <regex>
 #include <sstream>
 
diff --git a/src/version.cpp b/src/version.cpp
index 1616341b..f132ea13 100644
--- a/src/version.cpp
+++ b/src/version.cpp
@@ -6,7 +6,6 @@
 #include <curl/curl.h>
 #endif
 
-#include "http.hpp"
 #include "version.hpp"
 #include "makernote_int.hpp"
 #include "futils.hpp"
@@ -20,7 +19,6 @@
 #include <fstream>
 #include <regex>
 #include <set>
-#include <sstream>
 
 // #1147
 #ifndef WIN32
diff --git a/src/webpimage.cpp b/src/webpimage.cpp
index c4302335..22bf202e 100644
--- a/src/webpimage.cpp
+++ b/src/webpimage.cpp
@@ -6,31 +6,16 @@
 */
 
 // included header files
-#include "config.h"
-
 #include "webpimage.hpp"
-#include "image_int.hpp"
-#include "enforce.hpp"
-#include "futils.hpp"
+
 #include "basicio.hpp"
-#include "tags.hpp"
-#include "tags_int.hpp"
-#include "types.hpp"
-#include "tiffimage.hpp"
-#include "tiffimage_int.hpp"
+#include "config.h"
 #include "convert.hpp"
+#include "enforce.hpp"
+#include "futils.hpp"
+#include "image_int.hpp"
 #include "safe_op.hpp"
-
-#include <cmath>
-#include <iomanip>
-#include <string>
-#include <cstring>
-#include <iostream>
-#include <sstream>
-#include <cassert>
-#include <cstdio>
-
-#define CHECK_BIT(var,pos) ((var) & (1<<(pos)))
+#include "types.hpp"
 
 namespace {
     [[maybe_unused]] std::string binaryToHex(const uint8_t* data, size_t size)
diff --git a/src/xmp.cpp b/src/xmp.cpp
index 133d38d6..5d19646e 100644
--- a/src/xmp.cpp
+++ b/src/xmp.cpp
@@ -8,10 +8,7 @@
 #include "properties.hpp"
 
 // + standard includes
-#include <iostream>
 #include <algorithm>
-#include <cassert>
-#include <string>
 
 // Adobe XMP Toolkit
 #ifdef   EXV_HAVE_XMP_TOOLKIT
diff --git a/src/xmpsidecar.cpp b/src/xmpsidecar.cpp
index 7aa8c380..11b64148 100644
--- a/src/xmpsidecar.cpp
+++ b/src/xmpsidecar.cpp
@@ -1,21 +1,14 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
-#include "config.h"
-
 #include "xmpsidecar.hpp"
-#include "image.hpp"
+
 #include "basicio.hpp"
+#include "config.h"
+#include "convert.hpp"
 #include "error.hpp"
-#include "xmp_exiv2.hpp"
 #include "futils.hpp"
-#include "convert.hpp"
-
-// + standard includes
-#include <algorithm>
-#include <string>
-#include <iostream>
-#include <cassert>
+#include "image.hpp"
+#include "xmp_exiv2.hpp"
 
-// *****************************************************************************
 namespace {
     constexpr auto xmlHeader = "<?xpacket begin=\"\xef\xbb\xbf\" id=\"W5M0MpCehiHzreSzNTczkc9d\"?>\n";
     const auto xmlHdrCnt = static_cast<long>(std::strlen(xmlHeader));  // without the trailing 0-character