Accidental Troll

My rule of thumb is 24 hours. It's not just about sweat - the human body is covered with bacteria and washing kills it. Too long without a shower and you do smell, though because it is you it's hard to tell because you're immersed in it yourself. Sweat just makes it more likely because bacteria feeds on water as well (hence why the pits and other crevices are likely to stink first).