We have 3 cat trees here. One is a tree I made out of 4" diameter fallen tree limbs, with shelves and baskets attached. Another is an Armarkat tree that is 3 years old; looking good and going strong, although I need to replace the sisal rope on the legs. One is a cheapie I bought from Ebay; I think it's a Neptune brand. I would not recommend the Neptune tree for anything but kittens or small cats, as it is very flimsy. In fact, I removed the tallest part of it as I am sure it could be tipped over unless attached to the wall or floor, which is not always practical. I sometimes move the trees around so the cats think I got them a new one lol. The Armarkat and the tree limb tree are incredibly sturdy on their own, with a wide base on both. I have also seen some tall, very heavy duty carpeted trees at my local pet/feed stores and even Meijer's that appear to be made out of 2 x 4 posts instead of the cardboard tubes for the legs. That brand name is Wayfair. If price is no object, Molly's Cat trees are really well made. There are a lot of options on Ebay and Amazon for trees. If your local pet stores will allow it (mine does) , and your cat is used to wearing a walking harness and being in public around lots of people, kids and dogs, I'd try bringing him or her there to trees out for stability and fit. In general, I'd recommend buying the biggest well built tree you can afford, or even 2 or more smaller trees.