AAAAARRRG, scream. I replaced the blade in my Matelli rotary cutter yesterday, nicked a template this afternoon and now I am back to where I was before, no clean cuts. One new blade is left in the pack but oh that cutter was smooth as silk. Cutter gets the last blade tomorrow.
I put a sticky note on the top of my machine when I change a needle with the date, size and needle type. It is the only way I can remember.