'for' before 'a long time'?

[Mehrgan]

Hi,
Would it be always wrong to use 'for' before 'a long time' as in the following sentence?

'We've been married a long time!'

[emsr2d2]

No, you can add "for" if you want to. It's not obligatory.

[Mehrgan]

Is this arbitrariness just for 'a long time'? How about other phrases indicating time used in a present perfect tense?

[5jj]

We can omit 'for' before most time expressions. The omission is rather informal.

I have lived here (for) ten years.

[Chicken Sandwich]

Is this arbitrariness just for 'a long time'? How about other phrases indicating time used in a present perfect tense?

NOT A TEACHER

It is possible to leave out for (but not usualy in negative sentences):
- They've been married (for) ten years. (with or without for)
- They haven't had a holiday for ten years. (you must use for)
(English Grammar in Use - Raymond Murphy)