Let's say a pair of 20-something people meet up casually and start to date. How long - generally - do you think they should date before they legally marry and legally tie their worlds together?

I'm curious what everyone thinks!

I think that it depends on, and is is up to, the individuals involved. We dated for 5 years and were still quite young marrying.

Forever,, even when married..set aside time for a old fashion date or two or three giggle

I think it depends on quite a few factors. 20-something really isn't an age where most people are fully mature, know themselves well, and know what they want for the rest of their lives. I recall being in my twenties thinking I knew it all, fell in love many times, thought this one was "the one", and having my thoughts, opinions, tastes, everything change and often.
Divorce rates are pretty high, so if you want a lifelong marriage, in my opinion you should date and live together first for at least 5 years. If you plan on marrying someone, there is no need to rush into it. You really get to know someone over time and especially when you live with them. I'm sure some disagree due to religion and upbringing, but how else will you find out if you are truly compatible, can deal with hardships, bills, illness, bad habits, disagreements, etc. I'm not saying it can't workout if you don't, but that your odds will be alot higher if you take the time to mature, get to know yourself and your partner, experience life together a bit, then get married. Marriage requires work, tolerance, love, trust, committment, laughter/fun, and desire to make it work from both partners. Too many young people & celebrities do it for the wrong reasons and too soon and then they wonder why it didn't last.
I take marriage extremely serious and don't believe in divorce. I dated my husband for nearly 2 years, then we got engaged and lived together for 6 years before marrying at age 32.

That's a difficult question. I got married when I was 21 and he was 22. Not long ago, so indicator to my age!

However, I think I still have some insight.

We knew each other for 4 years before we go married. I met him shortly after my teenage first love of 4 years broke up with me.. so I was.. 17?

But without going into my own story which is irrelevant, I think one should date at least 3 years. Longer in most cases, but at the bare minimum, 3.

I've become so repulsed by church teachings that push for short dating, short engagement. Then I look at these couples and think... are they really in love? My cousin went through that. Short dating period, then got married suddenly and had a kid, all because of social, family, and church pressures. Now they are divorcing. She never loved him.

Another couple in my family dated for a year. No one even knew they were together until they told everyone they were getting married. Since he was/is the youth pastor, they didn't want it to cause drama. Now I look at them and think... really? They never touch each other (hold hands, arm around each other, something!) and hardly ever kiss (they waited until wedding to kiss). I can understand a couple's inhibition for PBAs... but when you're young and in love.. come on.

I'm crazy about my husband. Was when we got married, am now. And I just don't see that in people I see who don't wait to get married.

I think the reason is because they hit the wall that every couple hits, the wall of nit-picking. The wall where just everything bothers you and you want SPACE! We went through it, and it was hell. I can not imagine going through that while being "stuck together." It took 2 years for us to get past the romantic new car smell of the relationship and into the nitty-gritty. If you've only known each other for a year? Then you're going to go through that when married. And it's not fun. Then you get into resentment, and you can't get out because you're married.

I was just reading "Renewal Coaching" by Douglas Reeves. He explains studies where researchers can tell within 15 minutes if a couple will still be together 15 years from now.

It has to do with respect for each other. If a partner shows disrespect for the other, holding contempt for the other's views or ideas or beliefs, that is a fairly sure sign they won't last. If they criticize, or cause the other to become defensive, those are all death knells.

So often it's not about length of time - it's about the amount of patience and respect and "calm discussion" ability each person has.

It's a great book - here's a straight, non-affiliate link for more info.

http://www.amazon.com/Renewal-Coaching-Sustainable-Individuals-Organizations/dp/0470414960