There are a few different variables that can help determine the life expectancy of your sleeper sofa. According to The Spruce, an important thing to consider is how it will be used. A good sofa bed that is being used as a sofa first, and a bed occasionally, may have a longer life when it comes to the sofa bed mattress. Similarly, a sleeper sofa that is predominantly used as a bed nightly may wear out a lot faster. It also depends on what is happening to the bed. For example, if a sleeper sofa is being jumped on by kids, it may have a shorter lifespan than if it being treated gentler.
There is no hard and fast rule about how long a sleeper sofa will last. Some brands are more reliable than others. If you are looking for a starting point, reading reviews is your the best choice, and ask your friends and relatives about their experiences (especially for back pain).
There is no Hard and Fast Rule
Ultimately, there are a lot of variables. Your best bet is to find one that works for your requirements, is rated well, and comes from a reliable American brand. There are many things that will influence how long your sleeper sofa will last, including how often it is used, and how if it is treated well. If it is treated quite nicely and used less often, your chances of it standing the test of time is better.
So happy couch hunting! Make sure you figure out what you want, what your budget is, and shop your heart out accordingly.