I have all the sizes available for the rotary cutter. I find that I rarely use the 60mm. My favorite is the 45mm in the ergonomic cutter. It gives me the most control and is most comfortable to use. I use the 28mm to cut out garment patterns--especially helpful with slippery, silky fabrics. I have only used the 18mm one once in a class for miniature quilts. I think I could have accomplished the same thing with the 28 mm. Hope this helps.