What do you think is the right length of time before marriage?

[Totemoneru]

Assuming a couple were both wanting marriage and money wasn't an issue, how long should they be in a relationship for before tying the knot? Or is there a milestone that needs to be reached? Such as living together.
Will add a poll for ease but interested in people's reasoning.

Ideally I'd say 2 years before living together, then a year trying that, so at least 3 years in total. But that's a yardstick and a certain bending of the rules a bit may do no harm. Living together for a year being the most important bit, you only really know them by doing that.