A definite must in my books. However I do suggest you get some way of reminding yourself that you have the plate on and do not switch to zig zag etc. or you will have lots of broken needles. I have a bright pink clip that I put on the extra spool holder on my machine so it is in sight all the time. When I change plates I store the clip on the plate before i put it away. It has saved me a lot of needles and bad language.