If your pet sleeps on the couch or in the bed with you it will be difficult for them to jump up to their normal comfy spots. There is a wide variety of stairs and ramps on the market today to accommodate not only your decor but your pet's size as well.
It's important that your pet be able to go to the bathroom without discomfort. For cats, you want to make sure they can still enter and exit their litter box comfortably switching to a litter pan with lower sides if needed.
Most cat beds are soft but you want to make sure it is supportive as well. There are cat beds available that are similar to orthopedic mattresses for people. Location is also important. If your cat is having trouble with stairs place the bed on the first floor.