The round perches are a bit small for my larger (12-14lb)  6 yr old cats.  They can't sleep together in the perches.  Two of the boxes are small, the others are just right.  They don't use the ladders, but they do like the scratching posts and they like the height of the perches and like to sit on the platforms and look out the window. They also have figured out they can use the port holes in the boxes to move between levels.  It is very sturdy and my 3 larger size cats cannot knock it over even when all 3 are on it. Very well made.  We have tried other cat trees and had to send them back because they were so skimpy and would fall over setting off our burglar alarm !   We have only had the condo for a couple of weeks, as the cats get used to it I am sure they will explore it more.