The mattress in my Designer wasn't good to begin with (according to my bad back) and after 17 months of full time use it had to go. I just replaced it with a Sleep Number RV King with Radius corners this past weekend. I wish I had done it 16.5 months ago. And the new mattress isn't heavier than the old one so the gas shocks hole up the bed perfectly for access to the under bed storage.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof