The BedRug in my truck is most likely 16 years old and it looks great. It has always been covered with a canopy or tonneau. I have standard rails for my hitch so I had to cut openings in the mat. The comment regarding firewood is true but I have had no problems bringing it clean with a shop vac. When it gets rained on while towing I make it a point to leave the tonneau open when it is not raining to air the rug out. Sometimes this takes a week and I have not experienced any rot or degradation. My knees thank me for owning the BedRug.
I had a custom bed mat which did not go when I sold a previous truck. I cut a chunk out of it and use it as an entry mat for the trailer. It gets soaked, muddy and filthy but I just hose it off and am good to go. It dries quickly. The material they use is really tough.