Personal Experience: 

If you have multiple cats, or have very playful kitties, a large cat tree is suggested. You will find that they run out of energy a lot faster with a large cat tree than they do a small one. They will play, sleep and scratch the post on this all in one large cat tree. 

Take a look at the 5 options below:

Cat Tree #1

Amazon Link: https://amzn.to/3HKUnAk

About Product: 
This extra-large, multi-level cat tree condo is furnished with two larger, plusher condos, sisal-covered scratching posts, and a perch hammock for kittens and cats.

Colors: Smoky grey, light grey, and beige
Size: L 16.9 x W 16.9 x H 40.5 inches

Cat Tree #2

Amazon Link: https://amzn.to/3OAVCnL

About Product: 

This cat activity center with scratching posts and a scratching board has 2 cat caves and a hammock!

Colors: Smoky grey and light grey
Size: L 23.6 x W 19.7 x H 61 inches

Cat Tree #3

Amazon Link: https://amzn.to/39KPF9h

About Product: 

This at activity centre, tower condo has scratching posts, hammock, and plush perch.

Colors: Light grey, and smoky grey
Size: L 21.7 x W 17.7 x H 56.3 inches

Cat Tree #4

Amazon Link: https://amzn.to/3xSZM3T

About Product: 

This cat condo is covered with sisal scratching posts, hammock, and a large kitty playhouse!

Colors: Smoky grey, and light grey
Size: L 36.61 x W 30.71 x H 62.2 inches

Cat Tree #5

Amazon Link: https://amzn.to/3xSF7g4

About Product: 

Cat climbing tower with furball for small to medium cats. This multi-level cat furniture condo with scratching posts, top perch, and ladder for all indoor kittens.

Colors: White and Grey
Size: L 19.6" x W 19.6" x H 51" (50x50x130cm)