Cleaning a ball after every session of bowling is a great idea. I find my reactions to be very consistent week to week. But just remember a cleaner doesn't get the deep deep oil out. Once your ball starts to lose reaction or seems to act differently, that's when I go to the pro shop and re-sand and re-polish (if it's polished) so I can get a like-new reaction. I've done this religiously with my Paradigm Passion, and it's still moving and hitting like day one with roughly 400 games on it.
