A milestone can be meaningful because of what it lets you stop fearing.

Achievements are usually valued for what they add, but some of the important ones matter for what they take away. The savings that end the arithmetic before every small purchase, the result that closes a question you had stopped saying out loud. Relief is the real content there, even though relief photographs badly and makes a poor announcement.

If you reached something recently and felt oddly flat about it, ask what fear went quiet that week. Let that be the thing you mark.