You've been a geek your whole life, and your granddaughter shows you how to do stuff on your phone.

xpd:

 

.... the 6 year old is beating me at Disney Infinity.......

 

You don't even know what that is...

ubergeeknz:

 

the cool kids already moved on to Snapchat, Instagram is so last year

 

Snapchat? I used to play that with my Mum when I was a nipper.

when you can whistle while brushing your teeth.  (dentures)

when your once proud six pack starts to turn into a 30ltr keg or when you kneel for 5 minutes and it takes you 10 minutes to get back up 

Athlonite:

 

when your once proud six pack starts to turn into a 30ltr keg or <snip>

 

... or when you fall asleep after the first can 

When you have to get up to pee in the middle of the night, every night.

You go to the doctor with any kind of problem and he tells you it's just part of the aging process. Suck it up, princess.

you know you are getting old when you start threads about getting old

Staying out past midnight is a struggle without medication.

This (youtube link, Billy Connolly)

You know you're old when you remember when flies stayed dead

You go to a bar and everyone else (except your mates) looks under-age.

Strippers call you sir.