I seem to be fortunate to have few automotive electrical issues over the years. As general preventative maintenance on old cars. Just cleaning and treating all ground connection usually gives some benefit.

Sometimes it can be subjective like I think the headlights are a little brighter than they where. Certainly the grounding system was not designed nor intended to last thirty to forty or more years without maintenance.

That said on very modern cars it can be really difficult with some electrical problems. Some can be the intermittent ones that could drive you insane if you were not already there.

I have a long list of things to check and do before putting an old buggy into heavier service. It takes less time to lubricate everything that is needed. Than having to repair a broken up hood hinge that seized and tore the metal out. Or find and replace a power window and regulator.

Few probably even consider lubrication of the window channels with silicone. Then there are the sunroof components. Old dried up lubricants are doing nothing where there is need of lubrication.

Even just lubricating the door hinges etc also makes the car feel better to you. I feel on most examples it was years and years since things like this were done. Even the locking tumblers are probably neglected.