We have 5 cats, one of whom is in the neighborhood of 25 pounds... Affectionately known as Jabba the Cat. He's not a Main Coon or anything, he's just a big boned cat who is fat because he won't do anything but eat and sleep. All of the places he can fit into on this tree handle his weight easily. I doubt the upper, free-standing tiers could boast that, but he's so fat and lazy I"ve never seen him hit the 3rd tier, much less the upper ones.3 of our 4 average sized cats (all between 7 and 15 lbs)have been all over this thing, up and down and sideways and wrestling and fighting and falling off and it's handled their abuse smashingly well. So far the only signs its been used (after about 4 weeks of boisterous tomcat play) are that both of the fuzzy mice are missing their tails, but still attached to the rubber bands, and the roomba has torn up a little of the fabric at the floor level. Well, that and in spite of frequent vacuuming is usually liberally coated with 3 different colors of hair, all of which contrast nicely to the color of the material. The one non-shedder we have is almost the exact same color as the fabric used for the tree... Cruel irony eh?I have to say, whoever engineered this was an absolute genius. It is NOT heavy duty material, the cardboard tubes that the ropes are wrapped around to form scratching posts are probably tougher than any real wood you may find in this (its all particle board and cardboard) but once it was all assembled, the first tier actually supported my (VERY CAUTIOUSLY APPLIED) 230lbs. It's basically engineered in such a way as to support and strengthen itself, and at least in the short term has fared surprisingly well. It may be very tall, but its also wide based and hasn't toppled in spite of some pretty serious brawls over who gets the top cubby hole.I'm thrilled that I got something as functional as the 250$ 5' tree from Costco, and didn't have to drive 40 miles to get it. Half the cost, no gas and the FedEX guy even carried it into my living room for me.Highly recommended3-29-13 Edit. Its still going strong. Our largest two are over 20lbs now (one of them is over 25). The brawling over the cubby hole has expanded to the upper perch. So far nothing has worked loose or broken (well except the faux mice on rubber bands, they were torn off and lost long ago, but that was pretty much expected) I haven't had to tighten anything and it STILL hasn't fallen over yet. At this point I'm past disbelief with this unit. Its the highest traffic area in the house where the cats are concerned, and even the tallest perch supports a cat so big (yes, Jabba The Cat found the upper perches) his excess skin overlaps the edges all the way around.2-28-2015 Edit. Nearly Three years later. Cat tree is still here. The cubby holes are still hotly contested territory. Jabba the Cat is now pushing 30lbs. We tried putting his food on the 3rd tier to help with weight loss, but he either sleeps up there, or mooches from the neighbors. The rope wraps are showing fray from use, but are still firmly attached. Both ramps are intact. All platforms are intact. This cat tree has actually outlasted a considerably more expensive office chair that was purchased at around the same time.5-22-2016 Edit. Another year down. Still going strong. Wear hasn't progressed much further, though we lost Jabba the Cat and his Blonde brother; one to age and one to the negative side effects of feline obesity. We've had a couple more strays move in (though their combined weight is still a little under Jabba's) so we're at 4 indoor cats now. Our "newbies" are very young and boisterous, and in spite of its (for cat furniture) advanced old age; the tree is STILL holding strong. As its now become custom for me to buy and rehang catnip-stuffed furry mice, I actually drilled holes at their mount points to make it easier to purchase new elastic and hang them. One of the "newbies somehow managed to knock the lower ramp off, but I fixed that with a drill and a small carriage bolt.(Still) The most amazing purchase I've made on Amazon.