Well, I substitute teach during the week in 3 ISDs

I vacuum the dust bunnies probably 3-4 times yearly. mostly quarterly.
Ok, OP, back to you

Quoting a piece of your first post in this thread: "I'm wondering if in Win7 there is a series if suggestions to clean out the deadwood without removing actual in-use programs: things like the AppData and Roaming areas which seem to contain a lot of temp files." One answer: One thing I've been doing for some time: after making shortcuts to appdata local temp directory, windows temp directory, I use those shortcuts to goto said directories and delete everything found therein, mostly just before making image backups.