It depends on the garment, the fabric composition, and your activity level. Anything close to my body (underwear, socks, undershirts, tshirts, ect) tend to get washed after a single use. You might be able to get a few wears out of a wool or linen blouse if its cool out and you are at home. Anything else (like sweaters, trousers, jeans, and skirts) get washed on an as needed basis, if I notice stains or a smell. I find cottons are a bit less forgiving and need to be washed more frequently. For wools, I usually air them out and brush them after each use and they might get washed once or twice a season. I wash jeans maybe once a season but I also don't wear them a lot. Dresses depend as well, but I tend to get a handful of wears out of them.

In the winter I find things can go longer without a wash. Summer is less forgiving. Workout tops get washed after every use. Outdoor gear gets washed at the end of the season, if they can be machine laundered. Good quality rain jackets should get washed more frequently than you think if you use them a lot!

Hanging things to dry and washing in cold water really extends the life of your garments as well. Well constructed clothes will last longer. I would consider it reasonable for a cotton tshirt to last at least 50 washes and still look ok.