As an errand example. I schedule my dental appointments 6 months out. If my work gives me only 24 hour notice I have to be in the office for a meeting that didn't exist until now, it makes no difference if I live a 6 hour flight away or a 30 minute walk away.

Now do the same for a 1hr meeting at 10am or 2:30pm with a need to be able to dropoff or pickup school children at 9am or 4pm.