Strategy: when to build a new city?

[Vic]

I'm wondering when is the best time to build a city? People say all kinds of different things in this regard: early on, so it pays itself back and offers possibilities in the future => drawback: less mobility, can't move a city, and it's possible that lack of options will allow other players to swoop in and steal whatever electorate you were about to win.
Mid-game (3rd round specifically, but I don't know why): when your aristocrat tile supply is running short
End-game: If used them as (very expensive) tie-breakers before to ford the player about to win and to get a crucial victory point (I ended up tieing the player).
Never: I've heard someone suggest that cities are entirely useless because they can't be moved, are expensive and generate daughters.