It's the scratchpad script where you copy/paste into the about:config console. I just did it for the new v.115 release. I've done it previously but I don't have any set schedule. I guess 1x every six months (2x/year) seems sufficient but I wanted to see what others do.
Yeah, I do that too but every now and then I'll run the cleanup.js script. It always clears away a couple of deprecated prefs. I guess there is no harm in having those older prefs around but clearing them away seems nice.
You'll definitely want to run the prefsCleaner.sh script at the same time you're running the updater.sh script. The cleanup.js is more of a nice to do, than a need to do.