[_carbyau_]

> a couple is 3-5, but never 2

For me it depends on the formality. For example, a married couple is never more than two people.

[Daneel_]

Ahh, that's different than referring to a count of things though - you can't hand a couple of married people to someone, for example. But "Hand me a couple of screws, would you?" - I'd pass them 3-4 screws, not 2.