pack year - A number that tells how much smoke you’ve choked down like a

A number that tells how much smoke you’ve choked down like a sad, tired animal for 365 days.

'I’ve got 25 pack years. I don’t need a coffin, I need a smoke break.'

'You smoke so much you’ve got the brain of a burnt-out ashtray.'

'That’s why you wheeze like a dying dragon.'