Need tips on vac purging

Hey guys I got a question! I always hear people say when vacuum purging you want full vacuum, then I've heard a lot of other people say -29 hg! So which is it? Full vac or -29? I live in Maine and have no idea about elevation or sea level or any of that shit. Any help would be great. Also, when I'm vac purging my gauge goes beyond -30 hg. Any help with this would be greatly appreciated

Damn, what kind of pump are you running?

That is an extremely deep vac. So deep you are boiling terps at room temp.
Could possibly be your gauge...
Full vac IS about -29.5 hg

I think you are fine man..give the gauge a tap with your finger with vac running.