I feel like the Young Justice boys steal and borrow each other clothes. Like Tim and Bart absolutely swim in Kon's shirts since he's so tall compared to them, but Tim and Bart usually fit in each others clothes. If Bart would buy the proper sized shirts to begin with anyways.
Bart needs Tim (Max. Jay, and Wally) to buy his clothes because he just buys shit, doesn’t matter the size, if it’s male or female, part of a suit, onesies, rain cape, toe socks, price tag be fucked, so Tim and his dads are like “okay we have to make sure he had underpants in his size and some shorts okay?”