We eat A LOT of cheese in this house! Things also get a bit crazy at dinner time, so pre grated cheese is a good idea for us.
Grated cheese is much more expensive per kilo than block cheese, so for the cost of a few minutes time using a hand me down for processor and a snap lock bag, I'm all sorted!
I use an overly large bag so it can freeze flat rather than in a big lump. I just brush off what is needed when I need it, and hey presto - all done. Not life saving, but it does make things a teeny bit easier, and sometimes at the end of the day I needed every teeny bit I can get!