You know you are getting old when...

[Clippy]

... you start sentences with "In my day..."

[chef]

a single bottle of wine turns into a HUGE hangover (i.e last saturday morning)..

.. although it was part of my experiment "how cheap a bottle of wine is actually drinkable without complaint?"

..i've subsequently found out the answer is above 1€ 50 for a litre

[Mich the Tester]

... you start sentences with "In my day..."

or, of course, the other Daily Mail variants;
‘young people today…’
‘bring back the birch…’
‘these people who…’
‘living off our taxes…’
‘national service would sort them out…’

[Bagpuss]

When you make a sigh of relief as you sit down

[Spacecadet]

you hand over a tenner at the bar to pay for 3 drinks and you're stunned when you find its not enough

[expat]

... you start sentences with "In my day..."

"Of course, there were no mobile phones then".

"Of course, you didn't have the internet then".

[BrilloPad]

Not only policemen look young - so do politicians....

[DS23]

toilets are more important than shops when out shopping

[Bagpuss]

You forget the posts on CUK are just like the ones yesterday/last week/last month/last year

[expat]

toilets are more important than shops when out shopping

When travelling, I used to take every opportunity to get a drink; then it changed to something to eat; then to catch up on some sleep; now it's to go to the toilet.