2 weeks is my maximum but its usually before then, if I go out in town and get them sweaty they'll be in the wash
Shorts/ trousers is more like 5 days.
Tshirts/ shirts 1-3 wears depending on the weather.
Socks/ boxers after a wear.
The exception is my landscaping clothes, a pair of jeans and a shirt, not been washed in about a month, but they're literally only worn when i'm grafting. Absolutely foul smelling by now but i'm working outside with my sweaty foul smelling mate so it doesn't matter to me, not like theres a boss to it to say "change your clothes" either, informal cash in hand stuff.