I would say that it's very important for the bride and groom to think about the legal consequences of a wedding. Many people might spend hours talking about surnames or the wedding menu, but don't know, for example, that there are three possible matrimonial property regimes and are likewise unaware of the consequences each would have in the event of a divorce. If more people were aware of this issue, many problems simply wouldn't arise.
I frequently encounter situations in which one partner has simply failed to take care of financial matters. Without knowledge and documentation, you are at a severe disadvantage, because you do not have a clear picture of the existing assets. It is just as problematic if you have a good plan, but don't implement it in your daily routine, using all accounts to make all payments, for example. At some point then, all parties lose sight of the situation.