I remember taking the plugs out of my fathers car, filing the center electrode flat and gapping them ----if you keep your mixture correct, and don't burn oil the plugs can go a long time between filing/gapping --and much longer before replacing, I have been using the same 3X repro plugs in my "A" for over 35 years.
There is a small sandblaster that is made for sparkplugs (Harbor freight is one place that has them) ------don't use a wire brush to clean plugs, some of the metal from the bristles can be ground off and stay on the center insulater and make it not an insulater