Where caches live
~/Library/Caches: most apps, including browsers and chat apps~/Library/Containers/…/Caches: sandboxed App Store apps- Developer caches: Homebrew, npm, Yarn, pnpm, Cargo, pip, Gradle, CocoaPods, Xcode
Doing it by hand
You can open ~/Library/Caches in Finder (Go › Go to Folder) and delete folders for apps that aren't running. It works, but it's easy to remove something that isn't a cache, and you don't see which ones are worth the effort.
With Broom
Broom knows the cache locations of 260+ apps and developer tools and lists each with its size. Safe items start selected; your own files never do. Git repositories and iCloud-synced folders are never put in the list, and everything moves to the Trash first.
Questions
Is it safe to delete cache files on Mac?
Yes for real caches: apps rebuild them. Quit the app first. Avoid deleting anything outside cache folders unless you know what it is.
How often should I clear caches?
Only when you need the space. Clearing them constantly just makes apps rebuild them.