One day you’re having your first beer with your dad, the next you’re making him a grandad after a night of tequila shots. These are the rites-of-passage that sell aftershave and life insurance.

The moment they don’t tell you about is the one where the attractive girl smiling in your direction is doing so at the younger guy behind you. At that moment, look down.

The chances are you’re either dressed like a character from The Breakfast Club or a Babyboomer. Here’s how to retain your sartorial dignity through the transitional years…

You are not your son

There was a time when you looked great in a band t-shirt, sneakers and skinny jeans. And that time was before WiFi. Unfortunately, youth doesn’t come with an expiry date like your Visa card. It will probably take a brave friend or a loving spouse to point out that a baseball cap doesn’t go well with greying hair and ironic slogan t-shirts aren’t meant to be drawn tight over a pot belly.

Part of being a man is, well, being a man. Round up anything you wore in your twenties and either give it to your son, or the recycling. From now on, something with a collar is the minimum requirement. Anything with a bold logo, hood, or by Nike, Converse and Vans is over. Just do it.

After years of climbing the corporate ladder, there simply comes a time when you can no longer dress down. It follows on shortly from the time when you didn’t know how to dress up – as in turning up for your prom wearing a cummerbund, waistcoat, silver bow tie and half a pint of cologne.

The brutal truth is that you’re going to be a bit bigger around the waist than you were in your twenties, so tight clothes – especially jeans – are going to make you look like you’re sleeping in your car because your ex-wife burnt all your adult clothes.

Some teenage looks can still work. You can pull off cargo pants, but there should be no suggestion of a skateboard in how loose they hang. Black t-shirts and jeans are also an exception to the rule, because metal heads always go up to eleven.

You are not your dad

At the other end of the spectrum are the ‘young fogeys’ – more Prince William than Will.i.am. Even with an ironic wink, there’s still no need for any man to wear a cravat, cardigan or tan polyester slacks before pension age.

The problem is that as you fill out, you can find yourself falling off the end of the fashion world. Larger waistlines (and that means a 28-inch waist in some cases) steer pants into a shapeless, unflattering direction where material flaps around and the belt climbs upwards. This is how Simon Cowell happens.

Fight back by developing a relationship with a tailor you trust. Not only can he give your favorite jacket and pants a few extra years in action, but he’ll possibly correct basic errors you’ve been making all the way up to that point, such as wearing pants that break more than once over the ankle, or jacket sleeves that extend beyond the cuff.

How to nail it

Accept that you’ve reached an age where fashion is replaced by style. In fact, embrace it. This is your time to define yourself with a proper suit, permanent wallet, or watch that doesn’t glow in the dark or play the Star Wars theme.

A word of warning, however. Read the men’s lifestyle magazines and you’ll see plenty of straight faced advice that defines style as a Savile Row suit or Patek Philippe watch only. By sheer coincidence, those same brands also take the first ten pages of advertising. No, this is about being the best version of you, not a parody of Jude Law.

The secret is to get a second opinion from someone you trust on what colors, cloths and combinations suit you, and to invest in a modest selection of quality items within that range. Then upgrade and tweak incrementally as the years creep by, working a plan. And if that sounds ridiculously simple, just take a wander around your nearest mall to see what wisdom there is within.