Closed cell foam pads over time

Hi Jeff

I’ve got a few old Z lights that are pretty squashed including the reflective one I would say they did well for the first 30 days or so then slowly got thinner and thinner as they compressed. the one I used in my G4 as a frame, it’s probably just as thick as a single section now though it’s folded four times. on the other hand I’ve got an old Walmart Blue pad that’s got 60 nights Plus and a lot of time under the dog’s pad 185 lb plus dog that still looks pretty good . I use it barreled  rolled in side the backpack for years ,there’s not much room for anything else, but it still looks good.

They can also get a bit heavier as they pick up dirt.

Some pads squish down over time, some don’t.

Convoluted pads like the Thermarest Z Lite or GG Nightlight gradually flatten out from the weight of you sitting or sleeping on them, becoming less cushy and (presumably) less warm. Longevity usually depends on how many nights they’ve been used. I’ve worn out a few cut-down Z Lite sit pads over the years.

Plain closed cell foam takes a really, really long time, and usually some abuse, to flatten out. Cheap blue foam, GG Thinlight, and similar can last for decades unless you store them under something heavy. On the down side, I find sleeping on rocks only slightly less comfortable.

Open cell foam, typically self-inflating pads like the traditional Thermarest line, gradually break down over time, particularly if you keep them rolled and compressed between trips. Store them unrolled with the valve open, keep them dry inside, and they can last for decades. I have a ~1990 JPW Paco Pad with hundreds of nights and days as seat/gear padding on rafts, that’s as comfy as the day I bought it.

You are the best judge of keep-or-replace for your Z Lite. If you are undecided, a new one isn’t that expensive, and you can cut up the old one for a sit pad. Like I did.

— Rex

Zlites pack out reasonably fast.  Ridgerests last a lot longer.  I’ve retired them, but only because they got torn to heck by branches and brush while strapped to my pack.