Annealing brass for longevity is certainly gotten important recently.
I found with the candle method, in my case with an alcohol burner, and 750 Templaq, I found I didn't get a colour change before my fingers got too hot.
I suppose it would depend on the length of the case and how hot your heat source is. With 30-06 length cases and a propane torch it has not been a problem IME. In fact IIRC 308 length cases have also not been a problem.
