Depends on the length of the mission.
Exactly!
Since there is no washer or dryer in the space shuttle, astronauts bring a change of underwear for each day they are in space. They also have a few extra shirts, shorts and trousers. The dirty clothes are placed in a bag inside the shuttle's airlock. Space station astronauts send their dirty clothes back to Earth in the space shuttle or Russian Progress cargo capsules. The shuttle and the Progress can also bring them clean clothes.