Protect empty space; usefulness sometimes arrives without an appointment.

A completely booked life has no capacity for the unscheduled, and a good deal of what matters arrives that way: a conversation that goes somewhere unexpected, an idea that needs an empty afternoon, someone who needs you today. Filling every hour with something useful reliably excludes the useful things that could not be planned.

Keep some space genuinely open rather than lightly booked. Resist filling it. Its value only appears in retrospect, which is why it has to be protected in advance.