What it does
Sets how frequently Shake It On shakes when conditions are otherwise satisfied.
How it works
The shake interval is a slider over six presets: 5s, 15s, 1m, 5m, 30m, 1h. The engine checks elapsed time on every tick (twice a second) and shakes when at least one interval has passed.
Where to find it
Settings → Shake Every. The slider snaps to the six presets.
When to use it
5 seconds is overkill unless you're fighting an aggressive presence system. 1 minute is plenty for keeping your Mac awake. 30 minutes works if you're just trying to outlast the system idle timer.