I just tested mine and it worked fine.

Now I need to get a new window. Just kidding.

I do try to test mine every few months - usually on a few sheets of paper placed over my mouse pad and looking for the 'hole'.

I've always wondered how many tests its built to withstand without wearout.

BTW, I hope that the seat belt blade doesn't come off while its in my pocket someday. Ouch!!