this brings back memories. so thankful my kids are adult size now. it was a journey for sure equipping both my kids over the years. buying replacements matching their growth. buying new bikes wasn't an option for us, not when the local used market is so good. they both ride adult Trek FX series bikes now, just like Wifey. of course the other challenge was getting rid of the old bikes every, or every other year. but again, not bad cuz there're always parents doing same thing! what was annoying was dealing with the rear racks with every bike change. we do family rides and everyone is expected to carrying something, especially when we go to the beach. flip flops, towels, food, water, lock, phone, etc.
BTW, there is a forum thread called "recreation and family" that you might enjoy browsing
Recreational & Family