This is my first time giving my rotary cutter a real workout, so I hope I'll
know when it's time to change the blade!

I might just think it's me, still learning proper technique! Far as I know, it's still sharp.
I've seen those sharpening devices - anyone use them? Do they work?
Harbor Freight - I never would've thought! I like to browse hardware stores - see all kinds of things that could be co-opted as crafty. Some of my girlfriends are the same way. We're secret female hardware geeks! Now I have an excuse to go to HF.