“There are two types of schedule, which I’ll call the manager’s schedule and the maker’s schedule. The manager’s schedule is for bosses. It’s embodied in the traditional appointment book, with each day cut into one hour intervals. When you use time that way, it’s merely a practical problem to meet with someone. Find an open slot in your schedule, book them, and you’re done.
But there’s another way of using time that’s common among people who make things, like programmers and writers. They generally prefer to use time in units of half a day at least. You can’t write a program well in units of an hour. That’s barely enough time to get started. When you’re operating on the maker’s schedule, a single meeting can blow a whole afternoon, by breaking it into two pieces each too small to do anything in.”