How long will a Thermarest last?

I have a full length Thermarest that I bought about 20 years ago and am wondering if it is still functional. I inflated it (it had not been used for 10 years and it was stored in my closet) today and tested it out and it seemed fine. However, I am concerned about dry rot and am hesitant to use it on a trip. Any thoughts?

I've got one that I still use. It is about that age. Still works for me. A little bit heavy compared to the new ones thought.

Did you store it flattened or "fluffed up" with the valve open? If the latter I'd think it's fine, as the Trest foam seems stable over the long haul. If rolled with the air evacuated and the foam flattened, the foam might not completely inflate.

Cheers,

I had one "de-laminate" on me during a trip. The pad was 9 years old. Basically the foam inside and the cover on the outside seperated, creating a large air bubble in the de-laminated section. Thermarest sent me a brand new one immediately. I was tickled pink!

I'd say fill it up, lay on it and see what you think, feel of it and see if the foam inside feels soft or crunchy. That may give you some idea. Leave it inflated for several days in the house and see how it does.

I have one that is 28 years old and still going strong.

My 3/4, purchased circa 1985, has two or three patches and it's still in the ball game.

I've two 3/4 length from 1976 ? Both have had to be resealed round the valve. One has since had it's seam come apart for about 10" it actually dethreaded, but the other is still going fine. They have served us well, so if your pad is holding air try it at home for a night. If it holds up, just enjoy it.

I have one left from about 1976, until a month ago, I had two from that era. I gave one away because I was buying a new one and needed room.

I last used one of these in 2005 on a four day trip and it was fine. They were always stored flat and without the nozzle being closed... self inflated and open.

I had three from that era, and I can't find the third one.

Since then, I have purchased 3 newer models, including the NeoAir.