While we love our natural latex (from flobeds.com, no affiliation!) bed, it doesn't last forever. We had to replace ours at 15 years - while it was still better off than a spring mattress, it still had become worn. It had valleys and clumps - basically the latex was somewhat broken down. Compared to the new mattress, the old was more brittle and would tear easy, while the new one was resilient and springy.

The difference between it and normal spring mattresses is amazing though. I highly recommend them!