When you say " messy older child" do you mean "strews tings" or "spills things?"
The merchandise sold at Macy's IKEA and similar stores are all sold to meet a specific price. You can usually get 5 years, if you are lucky. One dead giveaway is sewn in cushions, especially on leather couches. Another is the cushions proper. Cushions on a good couch will be SUBSTANTIAL.
Better brands are Ethan Allen (EA), Restoration Hardware (Resto) (I don't like Pottery Barn). I worked for Ethan Allen about 20 years ago, and have family that worked for Resto. Their couches generally have much better construction overall than the low to mid market stuff. Better quality fabric, solid cushions, substatial frames. Couches that can be reupholstered. My couch is from EA and is going on 15 years. It has been through three moves, and still looks fantastic. But I'm not as happy with EA as I used to be--I think they are going downmarket on some of their lines now and it shows in pricing.
I would not buy new, if at all possible. Resto stuff turns up on craigslist all the time. A friend found a 4,000 Resto couch (we looked it up) on Craigslist and paid about 1,000 for it. Owner simply tired of it and wanted something new.
Another option is consignment stores, if you live in a HCOL area. You can occasionally find nice stuff on consignment.