This cat tree is a 5. The score is a 4 because it does require a driver (fancy word for drill that can function as a screwdriver) to drive the 4 inch screws on the top part into the wooden post. They are pre-placed nicely- and frankly this is what makes it sturdy enough for my cat (he already destroyed an Amazon.com one) ... but if you don't have a driver with a philips head attachment you would be very disappointed so just make sure to borrow one and make sure it's a strong one. There are no pilot holes - that's what makes the top so sturdy- but you need the strong driver to get those screws all the way into the post! I did spray some cat nip spray on it to mask the bit of carpet off-gassing and that did the trick. He's all over it now.