you can get digital hygrometers (combo with a thermometer) from wal-mart or other major home hardware places. Get one with an indoor outdoor measurement so you can check two temps at once, theyre about $12-15. Ive heard of bps getting scale rot when they urinate on the UTH and it is not cleaned up and the snake lays in it. Of course this would be avoided by spot cleaning your enclosure on a daily basis and entire cleaning monthly, that is what I do at least.