Ambition becomes sustainable when identity can survive an ordinary day.

Ambition becomes dangerous when your sense of who you are only holds up on the days you achieve something. Most days are ordinary. If ordinary days feel like evidence of failure, the pressure never lifts, and you end up needing the next result just to stay level rather than to move forward. That arrangement burns people out long before their goals arrive.

Build something into your life that has nothing to do with achievement and that you would not give up during a hard stretch. Cooking, walking, seeing one particular friend. It sounds unrelated to ambition, and it is exactly what makes ambition survivable over years rather than months.