It builds up your immune system!
No really, i have a mate who cleans everything after use. He's ill most of the time and takes that much stuff to counter the illness its stupid. I get a bit of a cold after a heavy weekend but thats about it. (touches wood)
The rest of the house is quite clean. The cooker is worst, before a greek guy moved in for a few days it hadnt been cleaned for over 4 years! He attempted but gave in. Even im discusted with the state of it, but now it just wont clean. New piece of foil in the tray and its good to go