Do you need to replace your box springs when purchasing a new mattress?

If you have a set of box springs you should replace them when you get a new mattress as they wear out. If you have a foundation (rigid platform) and it is in good repair and sits flat you will get just as long a wear out of your new mattress as you will with a new foundation. It will probably void your warranty, but if you bu a decent mattress and take care of it you most likely will have no issues. You should not use a box spring with a bed designed for a foundation as it will wear prematurely. over 90% of the beds made today have foundations. Also a bed designed for a box spring should not have a foundation used on it. The innerspring on a platform and box spring bed are designed differently.