Ditto what djfishygillz said. Add to that the ease of purchasing one adult sized cage with accessories that fit (uvb light and hood, making drainage, blah blah). Some people keep babies in huge cages with a feeder cup, but I have enough trouble finding my chams in their cages right now and they're def. big enough. If I stuck a little two month old in a 2X2X4 I'd spend hours searching and assuming I'd lost him. Also, for me, once I had one cham that was sub-adult I wanted another of similar age, for future breeding but also so I could buy one size of crickets and feeders. If I get another, I'll do the same if possible.