Purgeable space on Mac, explained (and why you should not force it)
Purgeable space is data macOS can remove when it needs room. It is already counted as available. Here is what it holds and why you do not need to force it.
Guides
Practical guides to Mac storage: what’s safe to delete and how to get the space back.
Articles, page 5
System Data grew 50 GB overnight: what happened
A sudden jump in System Data has a short list of causes: an update, a snapshot, a runaway log or cache, or one app. Here is how to tell which, using read-only checks.
macOS Sequoia System Data huge: causes and fixes
A huge System Data number on Sequoia has a handful of usual causes. Check them one by one, fix the safe ones, and leave the system's own files alone.
Old iPhone backups and iOS updates on your Mac: find and remove them
Check whether you have local backups, decide whether you still need them, and remove them through Finder rather than by dragging folders.
Why is the Library folder on my Mac so big?
Library holds app data, caches and settings. It is often tens of gigabytes. Here is how to see what is inside and what to leave alone.
Find large files on a Mac (Finder, Terminal and a scan)
A few large files often matter more than thousands of small ones. Here is how to find them with Finder and Terminal, and how to decide.