We purchased a firm Serta Innerspring Unit mattress from Sears in 2013. It has become too soft for my wife and uncomfortable. First I tried to have the mattress exchanged for an “extra firm” mattress through Sears. All I got was a run around with them asking me to measure the “sag” in the mattress, which there is none, the mattress is too soft when you lie on it. I then wrote to Michael Traub, President of Serta Mattress Company; Brian Callahan, EVP and CFO; Gary Fazio, CEO; and the Customer Service Department at Serta. I was referred to Nick Wells at Serta, who politely told me “…your 120 day comfort trial, is outside the warranty period.” Nothing more they can do. Well…we’re not satisfied. She has a back ache and has not had a good nights’ sleep for months. Please don’t buy a Serta mattress. You’ll be disappointed in the end and you will have no recourse from the manufacturer, Serta or Sears.