Most pro athletes are done before forty. Even dream careers have a second half to plan for.

Even the careers people dream about have an ending built in, and in sport it arrives in the thirties while most of a life is still ahead. That is not an argument against chasing it. It is an argument for noticing that the chase has a second act attached, and that people who handle the switch well usually began thinking about it long before they had to.

Keep one other thing growing alongside the main one. A subject you are good at, a skill, a qualification. An hour a week stops the first ending from being the only one.