Some guys (and girls) simply don't know when to say when with, say, an old pair of socks with holes in the toes or a dingy old pair of briefs.
If you live with a slovenly son of a grandma (or the rarer dirty daughter of a grandpa variety) then you know they don’t mean any harm with their filthy ways, they’re just not good at letting go.
Maybe you should show them this cleanly illustrated (and full sized!) chart from How To Be A Dad, so they can consult it before slipping on a sad pair of skid marked briefs that belong in the garbage can.