It struck me how much space duplicates occupy only after I stumbled upon a full 256GB SSD drive that seemed mostly empty. It had files from old backups, cloud sync folders, and nested project ...
You don't need to download a third-party tool to find duplicates ...
If your Mac is running low on storage, chances are that duplicate files and photos occupy a significant part of it. If the number is low, you can get away by performing a manual search, a terminal ...
So, it recently came to my attention that Dropbox for Android, when syncing files, automatically renames all photos and videos to a datetime stamp, not preserving the original filenames as they exist ...