You don’t have to wash everything you wear after only one use. In fact, washing your clothes after wearing them just once will wear them out faster; perhaps you’ve never thought about it, but the fuzz that you clean out of the lint compartment in your dryer is composed of tiny bits of fabric that have eroded off, and other bits of fabric rinse away in the washer as well. Thus, the less you wash your clothes, the longer they’ll last. Plus, the less often you wash your clothes, the less often you have to do your laundry.
While the exact number of times you can wear particular pieces of clothing in between washes depends on how often you shower/how smelly and sweaty you are/how many hours you wear the garment/the weather, above you’ll find a breakdown of general guidelines. When in doubt, just evaluate how a garment feels, looks, and most importantly, smells, and err on the side of washing — and exuding extra freshness the next time you wear it — over not.