I'm afraid I'm guilty of not cleaning my machine as often as I should, however, when the sound of machine when sewing changes, I know it's time to clean and dust (I usually only do this for my sewing machine, not my apt. LOL-kidding, but my DH does the vacuuming, mopping and the laundry as I can no longer do those things). I also heard a tip on Fons and Porter the other day where a woman used a chenille stem to clean her machine, I tried it and it works really well.