Shirts…? Hah! My two boys we're lucky when one of them decides to so much as put on shorts.
99% of the time, if we’re at home, they wear only underwear or a pull-up.
We insist on some form of clothes when we have company over, but other than that - the first thing the two younger kids do once we get home is ditch their clothes. I’ve kind of just grown numb to it I guess.