My dad has lots more tees than I. He has some very nice ones that I love. I always raid his closet when i visit.
I think a lot of this depends on the kind of tee shirt. to me, they are just shirts. Some are very soft, drape nicely, and have rich, flattering colors.
I do laundry every two weeks or so, sometimes longer. I just wait until there is a big enough pile to be worth doing, so i don't have to waste water on a small load.
I still want to get down to a dozen tees. The older ones are finding their way into the chore clothes/rag bag, slowly. Of course the tees i like the most get the holes in them fastest.