Not a bad idea, certainly if you're off abroad, but a better idea to invest the time if you can in a quick look see to see how bad yours may be, after all with an auto, your options are a bit limited in starting if the starter goes, although I reckon if push came to shove (did you see what I did there

), you could bodge the contacts enough to get it working in an emergency.
You could probably get away with just the contacts, my plunger would probably still have worked ok for a while yet if I hadn't replaced it, just didn't see the point in doing half the job while I was at it

You can't polish a turd - but you can roll it in glitter.