I did need twice of how for a largest my chair needed on top of a rug this idea did the well very well. As usually got my idea at the Staples for my idea get there and get the best!
The char mat is working fine thus far. I have had it for about 2-3 weeks. There is a 1 year warranty so I expect it to last at least that long. I see no reason why it would not last at least a year. It seems thick enough