I suspect they do laundry as infrequently as possible. A combination of neglecting the machines, cheap detergent, and cheap second-hand clothes probably negates almost all benefit of regular washing anyways. You could probably wash Chris' 31 year old sheets in gasoline and brimstone, and never get rid of all the trace failure ground into the very atoms which make up that blanket.
I'm horribly wasteful, when it comes to clothes. I must have dozens of outfits I've worn maybe once or twice, that I'll have dry cleaned and then hung up in a bag - never to see the light of day again. I know I'm getting overcharged, but I'm just too busy (read: lazy) to do my own laundry more than once or twice a month, so I have the laundromat in the building do it for me. I probably wear undergarments about 5 ~ 10 times before I replace them. Meh, whatever, I still feel good about it. I like the feel of crisp new clothes, and I don't have any stupid kids I have to save money for.