I sometimes use a different small piece of yarn as a marker. If you are changing colors or need to fine a certain point use a marker. In the round I place a piece for a couple of rounds and just move them up with the beginning of the round. It is like with knitting, use :happydance: if you need to or the pattern says to mark it and move it for each row if necessary or pattern change. You can use a marker if you want to for your own as a remainder for you even if the pattern doesn't call for a marker.