In the teenager-motivating caper, we tell them to establish a structured study schedule with the 10–15 hours a week they have left after school, sleep, work, sport, gaming, writing emo poetry about that one classmate’s perfect sweep of shoulder blade, dancing, eating and so on. The idea is to carve out specific chunks of time where you’re focusing on a certain subject instead of cramming in bits’n’pieces of homework whenever you remember you’re supposed to be learning stuff.

For me, it’s an intensely hypocritical call to arms, since there’s zero chance I would ever regiment my life down to the level of ‘Wednesdays 4.30–7.30: Maths Revision’ (I would revise my maths spontaneously, when the mood strikes), but it’s definitely some advice that would have been both useful and ignored if I’d been given it in high school.

Thinking about this process in terms of the adult world gives it a different slant. If you’re wondering why the years keep flying by at a devastating pace when it seems like only moments ago you were stressing over maths tests, it can be interesting to spend a month or so tracking all your activities by the hour. Draw up a colour-coded schedule and fill in the gaps as they happen. If that stranger’s tattoo is correct, and time truly is all we have, it follows that we should track it with the same intense focus as we watch our telecommunications investments fade away like so many forgotten dreams. We should be acting like penny-pinching clock-watchers, greedily hoarding every precious second then blowing it all at the casino because we were feeling lucky.

Either that or investing it wisely for the future by learning new skills, working on a long-term project or re-watching The Sopranos and realising how much closer you are to Carmela’s age than the first time you saw these episodes, and lying down on the carpet for a few minutes while everything spins out of control.

As you get older, the things you haven’t done yet become the things you’ll never do. Go back in time a decade, waving your schedule, and what would you tell the 2008 You to spend their 10 free hours a week on? What would the 2028 You be screaming in your time-squandering face about? In short, if you were going to carve out two chunks of three hours and a couple of two-hour blocks every week, what you spend them doing?

I’ve already started work on my time machine by looking up prices for DeLoreans then wishing I’d never bought Telstra shares. That’s my Wednesday afternoons set in stone for the foreseeable future.