An umbrella is most useful on the day you didn’t want to carry it.

Preparation always feels like a waste right up until it does not. Carrying something you probably will not need is mildly annoying every single time, and the one day it matters it pays for all the other days at once. That trade is hard to feel in advance, which is why most people skip it. The cost is certain and small, and the benefit is uncertain and large.

Do one piece of prep this week that you resent. Charge the thing, pack the thing, do the reading nobody will check. You will probably not need it, and probably is not never.