In February 2010, Morris Villarroel started a 10-year experiment.

The scientist, based at the Polytechnic University of Madrid, had just turned 40 and, like many people after a milestone birthday, began to take stock of his life. Wouldn’t it be useful to have a more complete and concrete record of his life, he thought? Not only would it help him to remember more of his past; it might also help him figure out how to live the rest of his life more effectively, to make the most of his time.

And so he started to keep detailed log books of his every movement. Each day’s entry begins the night before, when he will make a plan for the day ahead. On the day itself, he makes notes every 15 minutes to half an hour detailing where he is and what he’s doing – whether that is a simple metro journey, a class at his university or an interview with a journalist, like me.

“I’ll write down now that I'm speaking to you. And then, more or less how much time that took and some of the questions you're asking,” he says at the start of our conversation. He’ll then review those notes later on “if I have a moment where I'm waiting in a line up in a supermarket or if I have to wait for a doctor's appointment or a meeting or a phone call”.