wildgoose brings up an interesting point -- "(haven't replaced a blade in so long that) I misplaced my stash of new ones and I started to get worried and ended up ordering some new ones, Ha-ha."
Common problem, and I did the same thing, that little plastic container of blades vanished into a drawer or box somewhere.
When a new set of blades arrived, I used a strip of Alien Tape and affixed the container right onto the back of the cutter end-cap.