I don't think it's for everyone. Generally speaking, once you live together, the female is expected to take on the traditional roles of a female (cooking, cleaning, etc) which takes the sparkle off the relationship.
Also, women tend to see it as a step towards getting married, whereas men tend to think of it as a way to delay getting married.
I think it is possible to get a pretty good idea of personality characteristics without living together. For example, you should be able to tell if your partner is tidy, responsible with money, a good lover, etc. with regular sleep-overs, and without becoming his pseudo-mother/wife.
Relax... I'll need some information first. Just the basic facts - can you show me where it hurts?