I sharpen my blades all the time. I love the sharpener I use from Joann's and with a coupon costs about $12. The sharpener I use is listed below. It has 2 sides coarse and fine. I use the fine side mostly. I rotate the blade 20 times and then flip it over and 20 times on the other side. I love it and the blades are always sharp after sharpening. I use the coarse side only when there is a bur on the blade. I have never had a dull blade in my sewing room.
I also purchase blades from Harbor Freight cost is about a dollar a blade. They come in a 2 pack. Love them.
http://www.joann.com/dritz-rotary-bl...rpener&start=3