Every commitment spends resources that cannot simultaneously belong somewhere else.

Every yes is also a quiet no. The hours, attention, and energy you put into one thing were finite and are now unavailable elsewhere, whether or not you noticed the transfer. People tend to evaluate commitments in isolation, asking whether the thing is worthwhile, and skip the second question of what it displaced.

Before agreeing to something, name what it will take the place of. Say it out loud. The commitment often looks different once its cost has a name.