I have several sizes but seem to use 3 the most. Those three fit surfaces in the house where I can cut most comfortably. One fits on my kitchen table (most of it) and gets used with bed risers underneath and when I am working with big yardage. Then I have my go-to one that covers the top of my 5 cu foot freezer that sits on bricks in my sewing room. (small apt and space issues). Then I have a couple of rotating ones that I frequently use on top of my ironing board -- love, love, love those for trimming up blocks to size. Figured out that cutting height took the pain out of my aging back and wonky, previously broken right wrist. The correct height for me = cutting accuracy.