I think it depends on climate and mat quality, but mine have been down for 10 years now and basically look brand new when I do my annual full-barn scrub down. Have pulled one or two up occasionally to fill in a rodent hole, but that's about it.
But, I also sprung for the nice full 1" ones. The "need two people to move this heavy sucker" ones. It's hard to find them in my area anymore, you see a lot of the 3/4" ones, or even people trying to pass off 1/2" ones as stall mats.
Mine are the same as clanter's. They were installed 23 and 24 yrs ago and still in good shape. I did my barn aisle as well in rubber mats. I don't know what the brand was but they are probably about 100 lbs as well.
Back in my day, we didn't have as many warning labels because people weren't so dang stupid!