I know in my heart that I can use 2 inch squares but find it so tedious to cut them. So I take misc scraps and first cut the biggest square that I can get up to 10 inches. The the next biggest from 8.5 down to 3.5. (I get a lot of scraps.) They are filed by size and when I am kitting up, I just go to the size I need and pull them for use. Not enough to do by color or design except for the 5 inches.
There are times I just want to cut out pieces and not sew. Lots of patterns out there for 10 inch and 5 inch squares that can be adapted for all the others.