Stepping up when the usual leader is out is the fastest way to find out if you’re ready.

Readiness is not something you can work out from the outside of a job. Covering for somebody who is away is the cheapest test available, because it is temporary, nobody expects perfection, and within a day you find out which parts you had completely misunderstood. It is also how other people discover you can do it.

Volunteer the next time the usual person is out, even if you do not feel prepared. Pay attention to what surprises you. Whatever you got wrong is now a specific thing to work on rather than a vague worry.