I have a new pressure cooker , primarily for canning, and the instruction booklet indicates that I should get the pressure meter tested before use, then yearly. Where? Why? Debbie

IMO, that can be filed under, "yea, whatever".  I suppose you could hook it to a source of known pressure somehow to check it.  Does it have a valve on it that you could put something like a tire pressure gauge on and compare that reading to the dial?

I have my pressure guage checked at the County Cooperative Extension Service.  Also, if you have a local appliance repair shop they may be able to test it for you.

Ditto what Kathy said - Cooperative Extension always did this. You only have to take the top, not the whole canner.  Of course mine was checked about 20 years ago and I haven't thought about it since!  So how necessary this is for a new one, I can't say. Mine was my mother's and is almost as old as I am!     I'm wondering how it went, Deb.