Common sense... is it always a good idea?

A common theme I've picked up on this week in class is that many "common sense" ways that people think they are strengthening their relationships actually end up hurting it. I remember someone in class was saying that a friend of theirs wanted to be sure that their marriage was going to last so he and his significant other cohabitated, which actually decreases the chances of having a successful marriage. I think being educated in these matters and following the advice of church leaders is the best thing we can do to strengthen future relationship.