Challenge yourself enough to keep your self-image current.

A self image gets out of date unless something forces an update, and only difficulty forces one. Without a genuine challenge, you keep operating on old information, which usually undersells you. Regularly taking on something at the edge of your ability is how you keep your sense of yourself connected to what is actually true.

Schedule one thing this year that you are not sure you can do. It does not need to be dramatic. What matters is that the outcome is genuinely in doubt, since that is the only kind of experience that revises what you believe about yourself.