I only use Oracal, Avery, General Formulations, 3M sign vinyl and Avery Chrome. I NEVER change my blade length for different vinyls..For similar vinyls, you change the cutter force, NOT the blade length... I have to change to a little higher force for Avery chrome. Similar sign vinyls, just a matter of a step up or down in force.. Blade length is always set where it is, for months and months, maybe at 6 months, when a little duller, I give it a hair more length to get more out of the blade.. I usually change blades at about 9 months.