Nothing, not even the stars in the heavens, will last for ever but my olfa mats have lasted a long time. True the most used lines are fainter and a little gutted but it doesn't seem to matter. I do use a mat smoother now and then to clean it as bits of batting fluff can get trapped. I do rotate the mat so all sides get the same wear. I have a rotating mat with a 12x12 grid that I use all the time for trimming blocks. If my Olfa ever gets too used on one side I plan to turn it over and use the other. So far I have had the matt I have now for about 15years and expect to get at least another 15 out of it. I don't know if the blue ones are as good as I have only had to replace a mat once because it got warped by sitting under a window on a hot summer day.
As for rulers mostly I use the one, three, and six by twentyfour inch rulers the most for cutting strips but also use the quilt in a day square up rulers six and twelve as for the rest I have a collection of three inch, four, five and six inch squares that are most useful.