Enlighten me about cat trees

[forgotten_aria]

So I've never owned a cat tree before. They always struck me as something that it was likely that my cats would ignore and then it would just clutter up my house, but I recently read that part of keeping cats healthy is giving them somewhere they can climb and stretch. So I started to look into them. I was hoping for one that used real tree stumps with bark, but they are horribly expensive (cat trees are fairly expensive in general.) So I looked around some more, and I think that this would be a reaonable tree to own. I espeically like that it's not covered in carpeting. It would fit behind the weight machine. It is, however, still a lot of money so...

does anyone have any wisdom about cat trees?

Stories about your cats using them, not using them, them ebing an important part of your cat's life or just something that made your friends go "ew" or somethign that collected dust, but it was expensive enough you weren't willing to throw it out?

I could just buy a 2x4 and wrap it in siasal rope.