We use them at work. Each usually lasts several years. I've been in my office 8 years now and am only on the second (maybe third?) one. Do they have different quality mats? If so, a higher grade may last longer and be worth the money. BTW, I don't think we've ever had to replace any on an annual basis and we have about 20 people in the office. I think we replace 4 to 6 a year. If that's right, then each lasts here about 3 to 4 years.