You leave clubs before the end to "beat the rush".
You get more excited about having a roast on a Sunday than going clubbing.
You stop dreaming of becoming a professional footballer and start dreaming of having a son who might instead.
Before throwing the local paper away, you look through the property section.
You prefer Later with Jools Holland to Top of the Pops.
All of a sudden, Tony Blair is not 46, he's only 46.
Before going out anywhere, you ask what the parking is like.
Rather than throw a knackered pair of trainers out, you keep them because they'll be all right for the garden.
You buy your first ever T-shirt without anything written on it.
Instead of laughing at the innovations catalogue that falls out of the newspaper, you suddenly see both the benefit and money saving properties of a plastic winter cover for your garden bench and an electronic mole repellent for the lawn. Not to mention the plastic man for the car to deter would-be thieves.
You start to worry about your parents' health.
You complain that ecstasy's "not as pure as it used to be coz you know that if you have some it will take about 48 hours to recover and anyway, you might look a bit of an idiot.
Sure, you have more disposable income, but everything you want to buy costs between 200 and 500 quid.
You don't get funny looks when you buy a Disney video or a Wallace and Gromit bubble bath, as the sales assistant assumes they are for your child.
Pop music all starts to sound crap.
You opt for Pizza Express over Pizza Hut because they don't have any pictures on the menus and anyway, they do a really nice half-bottle of house white.
You become powerless to resist the lure of self-assembly furniture.
You always have enough milk in.
To compensate for the fact that you have little desire to go clubbing, you instead frequent really loud tapas restaurants and franchise pubs with wacky names in the mistaken belief that you have not turned into your parents.
While flicking through the TV channels, you happen upon C4's Time Team with Tony Robinson. You get drawn in.
The benefits of a pension scheme become clear.
You go out of your way to pick up a colour chart from B & Q.
You wish you had a shed.
You have a shed.
You actually find yourself saying "They don't make 'em like that anymore" and "I remember when there were only 3 TV channels" and "Of course, in my day..."
Radio 2 play more songs you know than Radio 1 - and Jimmy Young has some really interesting guests on.
Instead of tutting at old people who take ages to get off the bus, you tut at schoolchildren whose diction is poor.
When sitting outside a pub you become envious of their hanging baskets.
You make an effort to be in and out of the curry house by 11.
If you don't settle down soon and have kids you'll have no-one to look after you when you're old and frail and incontinent and you can't go on p**sing your life up against a wall forever and think of how many brain cells you're destroying every time a swift half turns into 10 pints, and look at that, a full set of stainless steel saucepans for 99 quid, they cost as much as 35 each if you buy them separately, and you get a milk pan thrown in...
You find yourself saying "Is it cold in here or is it just me?"