We have two upholstered FS sofas that are six years old. They are the most comfortable couches I ever owned.

Overall, they are holding up well. There is some "gapping" between the seat cushions but I think this is mostly due to how we lay, not sit on our couches. I regularly rotate the cushions so that helps.

One thing I like about FS is their back cushions have a zipper at the bottom. One looked kind of flattened to me so I shoved a travel size pillow up into it and it is perfect again.

I also have a FS sectional in my basement -- it doesn't get as much use as upstairs but I love it as well.

I am shopping today for living room furniture. Unfortunately, our Flexsteel dealer closed the nearest one is too far away. I am going to try out Lazy Boy which is a little cheaper anyway.

5 to 6 years is about the life expectancy of a standard 1.8 to 2.5 polyurethane foam. A high density or ultra cell will last 2 to 3 times longer.
FlexSteel says they have a lifetime warranty on their seat cushions.
Stir_fryi, I would be on the phone to your dealer or FlexSteel about your cushions.

We bought a Flexsteel sofa and loveseat about 7 years ago and love it!! The quality is great, no complaints and I had looked at a lot of other lines while shopping.

I say, just go for it and you won't be sorry.