Test for OOB hammer fall. Cock hammer, pull slide OOB 1/4". Allow slide to move slowly toward battery while tickling the trigger, if hammer falls before battery the problem is the disconnector nose is worn. Ignition is fast enough to prevent the slide from going to battery and start extracting the case.
Brass fatigue will show a slightly shiny ring around the case internal web, usually mid way down. Annealing won't help.
Accepting the risk is complacency, don't. Please, be careful.
Powder measure, measure 10 - 20 powder drops to get an average. Most powder measures will vary 1-2 tenths of a grain.