solid rulers I've completely covered- as instructed- I had one small ruler I thought I would use up some 'left over' invisgrip on doing it just top & bottom- it did not work well- the pieces curled, caught and the ruler did not lay flat. so, I removed the pieces and when I had a piece large enough I covered the ruler again. for my 'circle shape cutter' I do have pieces - that one seems to work out ok- maybe because it is not as (firm) as the solid rulers- so has some give, can still be flat. before 'committing' to only using pieces on all of your rulers you might want to just try it on one- & see how it goes. for me using it as instructed worked out best - I've had it on my 6" x 24" and my 12 1/2" square rulers for 8 years now.