I'm with the other folks here. I spot clean when I notice, but I dump it all, clean/disinfect the tub/tank and put in fresh bedding about once a month. The LIQUID part of things tends to sink to the bottom and spread out, and sometimes they do things like crawl through the poop or bury it as they crawl around.

That said, I've got colubrid's too and they NEED things cleaned up a LOT more frequently than the BP.