A lifeguard recertifies every couple of years. Skills you don’t refresh quietly expire.

Skills decay quietly, which is the dangerous part. Nobody sends a notice when your ability to do compressions or speak a language has drifted, so it sits in your memory looking intact right up until the day it is needed. Recertifying exists because somebody worked out that confidence outlasts competence. The feeling of still being able to do a thing is not evidence that you can.

Write a short list of abilities you would be in trouble without, and test one of them this month. Run it, practise it, redo the course. Finding the gap on a quiet Tuesday beats finding it on the day.