Oh yes, I have a story on this...
Three years ago, I noticed my mattress wasn't as comfortable as it used to be. I decided to flip it and took a look at the manufacture date.
1998.
When July 4 came around, there was a big sale at Macy's. I had just slept on a really good one at a Hilton in Columbus and did my research to see what they had. It was a Serta and I got a comparable model to what the hotel had at a good price.
Not sure if I'll go 23 years between replacement again, but I think that old one (a Sealy) was one we got our money's worth from...it was originally Grandma's, she didn't want it, put it on a guest bed, and then gave it to me when I swapped her a bed frame when I got a new apartment.