When do you think it's been long enough to finally get married?

I know that people tend to wait until marriage seems appropriate, whether it be “When the finances are straightened out”, “When we’re through with college”, “After 3 years”, etc etc. I’m just wondering what others feel are personally the right time to get married.
Also, I know some people say “you’ll just know”, but I’m asking this more from a 60% logical, 40% emotional type of orientation.