My old mat was an Omnigrid self healing mat and I used to have to change blades quite often. I purchased an extra large Beba mat (the translucent kind) and since using this mat, I am getting a much longer life out of my blades. Of course this was one of the selling points the salesperson touted - which I didn't believe (I bought the mat for the size) but ... she was right!!

I think you are right on. I had thought I needed a new blade and I had a small mat right next to my machine and instead of getting up and wallking over to my big mat just quickly trimmed up something and was amazed at how good and sharp the cutter seemed. So I experimented with different mats, cutters and fabrics and the big mat was the culprit.

Mine seem to find one spot on a rotation that just won't cut no matter where they are on the mat.

I use Olfas and they seem to last me a long long time and through several projects. Like quiltstingz says polyester batting and some flannels tend to dull the blades faster. I have found that some of the white plastic mats also damage the blades. For me, a long time is 5 months not 5 years..... I use 60mm for more than 4 layers and 45mm for the other and I buy 45mm in 5pak. They are a little costly but that way I know I have a spare when it's needed, especially when at a quilt retreat!!

I bought one of these sharpeners from the Grace Company a while back and I love it.

http://truecut.graceframe.com/cart/s...sharpener.html

They supposedly sharpen virtually any brand, any size blade without having to remove the blade from the cutter. I have several different size cutters, three different brands and so far it works on all of them. It won't make a blade last forever, but has really helped to extend their life! I just run the blade through the sharpener several times after each project, or any time it feels like it needs it. I only paid $24.99 for mine. If you shop around, I'm sure you can find it for less than the $39.99 listed at the site above.

There is also a tutorial that shows how to use it here:

http://www.youtube.com/watch?v=75VDKOu-kqE

I was just going to say this...I just rotated my big mat (it's 72" X 32") It's a big pain to rotate because of all the bolts of fabric on the wall side of it....but I sure cut better with the "new" surface.

Mine last and last too. I rarely change a blade and it is usually due to a nick caused by those darn errant pins. I dont do a lot of layers and if doing a Buggy Barn technique with 8 or more layers, I change a blade.

A good mat is critical and I found out that some fabric with poly or other fibers can actually dull blades. I almost ruined a rug hooking cutter blade with some mixed content wool.

My favorite blades are Gingher. They are more expensive but outlast the others several times over for me.

I've been using blades I bought over fifteen years ago. My daughter just bought her first machine and supplies and gave me one of her new blades. After cutting one project, the blade doesn't cut as well as my old ones do. It could be the difference in the steel used by Chinese manufacturers. I know the quality of steel has been a problem in other industries..

Rotary blades
 

I don't seem to have a problem with my rotary blades, and I have cut loads of fabric without changing the blades. Have you checked to see if the blades are put in backwards? That can make a big difference. It's worth a try. Hope you have better luck.