I have something in common with Prince Harry: we both turn 30 this year. While he's been working tirelessly on the Invictus Games, I've been trying – and failing – to come to terms with waving goodbye to my twenties.

Here, to mark the tombstone – I mean milestone – of our 30th birthdays, are 15 life lessons that every man should know by the time he hits the big three oh.

1. How to cook a signature dish

No, " mean beans on toast" does not count. You're 30 now, man – you need to have at least one dish in your arsenal with which to impress your friends.

Top tip: perfect the Sunday roast as its praise-to-difficulty ratio is stacked in your favour – people are disproportionately impressed by an ability to cut up potatoes and shove them in the oven.