I personally know people who have been dirty for decades. A friend of mine "inherited" the stewardship of one such person and he was a miserable bastard until he died of cancer and the only people who knew him regretted that it didn't progress faster. He was a drag on the few people willing to associate with him (neither his mother or daughter among them) both emotionally and financially. I myself helped clean up the disgusting mass of cigarette tar filled beer cans he left in my friend's house after he passed.

So your mileage may vary I suppose. And that's about all I'll say on the matter.