I haven't read all the responses so this may have been mentioned. I don't cut the length of the strips, but square up as often as I add rows. That sounds like it takes a lot of time, but it doesn't. Sometimes its just cutting a corner that isn't quite square. The other thing I do is cut the strips for the last time around a 1/4 to 1/2" wider. Then when I square up the final block there is a little to work with to make them the same size.