1.Cohabitation is a good idea. The biggest advantage of cohabitation before marriage is that it gives both partners a fair idea of how it would feel to be married to the person. When dating, people naturally put their best foot forward but sharing a life with the same person can turn out to be a different ballgame altogether. Living together can be a good way of getting to know about the other aspects of your partner and get a feel of the commitment and practical responsibilities that sharing a life and home demands. Cohabitation lets you know how being married is different from merely dating your partner.
I disagree with you, because even without cohabitation both partners can get a fair idea of how their partner can be after marriage, because as we know before establishing relations every person first of all determines all sides of his or her partner and only after that he gives his agreement. I mean not before marriage, but before starting relationship.
But where is warranty that they can know about each other if they didn't live together. May be you think that they can meet often but it not mean that they show their all sides and negative and positive. Of course they show only their positive side.
Ok I agree that they can know each other characters better but why after cohabitation when they married they divorce where is the evidence that cohabitation helped them. Over 30% of partners which married after cohabitation are divorced, according to sociologist Andrew Cherlin of Johns Hopkins University.I think most partners are didn"t show their true face before because if they do so may be their partner stops communicating with them and only after marriage they start to show their true face.
I disagree with you how they can hold themselves to not show their true face I think its impossible. For example they live together 2 years and during these 2 years they hold themselves and about divorce, in my opinion they have another reasons to divorce but we cannot say that cohabitation is 100% of good living together in future.