Check or turn off Reserved Storage — via Microsoft Learn

A Mac that shows almost no free memory is usually fine: macOS keeps recently used files cached in RAM so apps reopen faster. The number that matters is the Memory Pressure graph in Activity Monitor, which combines free memory, swap and cached files.

The Login Items screen often shows vague names that don't tell you which app installed what. An undocumented command dumps macOS's full list of login and background items, with the app and file behind each one, to a text file you can read.

Need your Mac to stay awake during a long download, render or presentation without changing your sleep settings? The built-in caffeinate command holds sleep off for as long as you say, then everything goes back to normal on its own.