For users looking to recover some much needed disk space on MacOS after years of installing and upgrading brew packages, I have some good news for you. Homebrew comes with a command to periodically cleanup unused resources.
brew cleanup --dry-run -s
The cleanup dry-run command shows you the location of files/folders that homebrew think sis safe to remove. It also returns an approximation of the total disk space that will be freed after the files are removed.
After a thorough review of the output of dry-run, use the following to permanently remove all the files
brew cleanup -s