High waters and worn knees

I just can't keep this boy in jeans. He wears thru the knees because he's either pushing cars and trucks around or playing tackle football; and if there's no holes they're above his ankles! I resorted to putting patches on the inside of some of his newest jeans to keep them alive longer, I know, lame. What's worse, high waters or holey knees? For me, it's high waters, so it's time to get to WalMart and buy more jeans!