Yes people should live together before getting married Okey so let get one thing strait, this is not talking about testing the waters or testing the relationship if you have to test the. Your questioning if your doing that then young need to get married. Now if you both really love each other and you both have all ready talked about getting married or maybe your all ready engaged to said person then to me I think it is extremely important to move into get her before you walk down the aisle.
By living together you get to see the others living habbits, can you still love him if he leaves the toilet seat up, can he still live with you when you clog the drain with hair, can you both handle money and share the stuff in the house. Are you a neat freak and he a slob. Can you work together and be happy. These are not questions to find out after you sink all you money into a wedding these are things to find out before hand. Move in with each other for a while get really used to how both of you live and work your odd habits likes and dislikes.
And yes some people may say it's a sin well if you think that then don't move in together before hand. It's your beliefs love by them this is just my belief and that is to move in before you get married.