the Simmons Maxipedic mattress has been an excellent purchase for the price.  With proper care this mattress has already lived up to expectations.  After a dozen years it is still comfortable, easy to sleep well on, clean, and shows absolutely no sign of any excessive wear.  It seems it will be able to hold up for another dozen years.  My conclusion is that it is extremely well made and I will buy another when it finally becomes necessary.  In the meantime I will continue to enjoy a good nights' sleep.