Probably matters more how thick the fabric is and how good the stuffins. Reminds me I own an old sofa with some wire actually in the back!

Vote for detached cushions you can unzip and restuff being the most durable. If for no other reason than you have two sides of fabric to wear out/ choose from.

We have a couch and loveseat with the back cushions attached and I would never buy this style again! It is very difficult to unzip and change the stuffing from one pillow to another (I sit on one end of the couch to watch TV and eventually the back cushion began to deflate after a few years...what a pain trying to switch the innards of the back pillows). You can't flip them front to back...it will cost me a fortune to have the furniture slipcovered...ugh! Bad purchase on my part.

I have a sofa and love seat with attached back cushions, but they are zipped on and you can un-zip to detach. But because of the shape of the back, the pillow on the left always goes on the left....sofa or love seat.
Attached pillows don't get "slouchy" looking as fast but when they do....the only way to fix that is to re-stuff them.
Linda c

In my opinion loose back cushions are the way to go. The attached cushions tend to rip across the back where they are sewn in. The zippered back is an option but it can be difficult to zip the cushions in place. The disadvantage to the loose cushions with kids are they end up on the floor. The advantage of the attached cushion is they look a little neater. You can rotate the loose cushions and they are easier to fix.

I bought a sofa from Rowe a couple years ago that had no back cushions at all. Just a stuffed back. Love it. I used to get really sick of messing around with back pillows entirely. I had forgotten until now what a pain those pillows could be, lol. I guess I vote for no pillows!