i change it every session, and clean it with isopropyl an salt every third session..
one night i was rather sloshed of a few bottles of green label evan williams (which is basically 12 dollars a liter, to show how cheap the whiskey is..)
and i felt as if i was going to be sicker in the morning if i just slept on the liqor now...
so i took a couple chugs of bong water and badda bing badda boom, i was projectile vomiting everything i had in the earlier hours of the morning...
also, when i lived with a few people i had a roomate who would pick weed off my plants so a few nights when he was passed out id put his hand in bong water, and sure as shootin, he'd pee himself and knock the bongwater right on his carpet..everytime.
when asked why there was bong water down there i always replied, well you wanted a bong hit last night so i came down with the bong.