I used the Tri sharp (blue with sandpaper/diamond discs) so much that I wore out the discs. I then purchased the Orbitol sharpener ($37 Canadian, handles all sizes of blades). It too works well but you never get a blade a sharp as a new one. I figure on the first sharpening it is about 75% as good as new and lasts about 3/4's as long, second sharpening 50% and third sharpening 25%. Neither of these sharpeners will take out nicks but will make your blades last longer. The best bet may still be to stock up when blades are on sale. Dull blades make for miserable cutting and will damage your mat. Kleen Cut blades (an Olfa clone) regularly sell for $2.99 at Len's Mills and once in a while they are on for half price. That's when I buy a couple of dozen and then further extend this supply by sharpening each a couple of times.