I use 2-3 pipes/day and rotate through them. Only run a cleaner through them if they get wet. Next morning I run a cleaner through each of them and set them in the rack to dry and grab 2-3 more for the next day. Having 15 pipes or so means they get to rest a week or so between smokes usually. If ever they taste or start to smell sour, I dab a cleaner with Everclear and run the cleaner through as well as swab the bowl with the cleaner.