When installing a new blade place one little black dot on the outside of the blade near the top with a permanent marker. Allow to dry and cut a scrap of material and carefully glance down at the dot to determine if the blade is rolling smoothly around. Also when turning the blade around to the opposite side to get extended use before discarding, put two small dots on the outside of the blade which will again be used to check for rotation after tightening and will be a reminder that you are now using the second side of the blade. I find this to be very helpful.