1. No. Annealing is done to return the brass to "factory" softness, so that it's less likely to crack/split when being resized. Brass gets harder from "working" it (i.e. expanding during firing, shrinking/shaping during resizing). If you haven't fired or resized it, it isn't any harder.
2. A popular induction annealing model, the
AMP Annealer, consumes 1 piece of brass as it heats it up to determine what default setting that brass needs to be perfectly annealed (why it has to OVER anneal it? I don't know, ask the manufacturer or someone smarter than me (there's lots)). If you use a flame annealer, you typically buy tempilaq 750 and paint the inside of a case neck and let it dry (I do 5 at a time so I can get the timer setting right without waiting for paint to dry again...). Then set up your flame annealer for the MFG-recommended exposure duration and watch to see when the tempilaq turns clear indicating the tempilaq as reached 750F (and the brass is pretty close to that). Out of pure curiosity, I sacrificed 2 pieces of brass because I wanted to know how much longer past 750F it took for them to glow (which is hotter than I wanted to take them).
3. Some people never anneal and get 5++ firings (liberal bastards). Some people anneal every firing (conservative fudds). You can anneal as often as you want. In
theory, as the brass gets harder it will affect springback and you
may need to adjust your sizing dies over the course of the life of brass to get the same shoulder setback. How much is that? 0.5thou? 2thou? I have no idea. Annealing, outside of some claiming consistency on resizing, is ultimately extending brass life via how many times you can resize before splitting necks. If you fire the brass 4 times and get loose primer pockets - you're done with that brass, regardless of how perfectly soft your necks are. For that reason, some guys know they can't get more than [X] firings from brass before they blow primer pockets, and if that number is low enough that they never encounter split necks before primer pockets go, why anneal? Hard to argue with them, but I like playing with fire.
Additional advise - 750F is hot as shit. Don't let them sit for 20 seconds on a baking sheet and then try to grab one and see if there's an annealing line. Use some pliers or wait longer. Don't ask me how I know.
