I agree and disagree...it's according to your situation, like you said, but babies is tubs too big can easily cause stress which leads to refusals. The Vision tubs are 18x7.5x3.5 I think...this is a decent size tub but not too big. Balls can easily stay in them up to 600-700g if need be. I definately wouldn't get a hatchling tub unless I was planning on breeding every year.