I walk to the train every morning along a similar route. Sometimes I’ll switch it up—mostly out of some tinfoil hat paranoia I have about some nefarious character learning my routine and luring me into the back of a sketchy van with a promise of ice cream—and sometimes I won’t.

Separate from the variety I intentionally inject, I’ll also vary my route based on traffic. If I can avoid coming to a complete stop while still walking towards my destination, I will. In these moments, I’ll make a decision when I come to the intersection.

If I apply this same ad-hoc approach to scheduling my day, however, there will be significant consequences. I remember being of the age where many of my friends had jobs where the hours and shifts would change every week. Until the next week’s schedule was made, it was hard for them to make plans for the hours that could be taken up by a shift.

If I open my inbox every morning and allow that to dictate the flow of my day rather than planning that our ahead of time, it’s unlikely that I will accomplish much of consequence in the aggregate. Every decision made on the fly draws from the my finite well of attention.

When your work involves other people, as it almost certainly does, it’s downright irresponsible not to be intentional about the flow of your day. Some things are fine to schedule on the fly, and others are decidedly not. Protect your time.