I taught a string piecing class and after everyone stewed & fussed over which color strings they were going to use (matched) I had them put them in a brown paper bag and then trade with the person to the right/left of them. You should have heard the groans! After you get used to it, it really is freeing. Of course I never had any problem being free to start with. My mother was a string quilter from waaaay back. I do like to have the center strip the same color because of the secondary design it makes but it's not a must.