actually the key to a prenup is realizing that they are strongest the first 6 years of marriage and best for protecting SPECIFIC items. Collection of X or vehicle or even a house.
A 25 year old prenup is not going to be as strong as a prenup that is only 1 year old.
Only if the property protected by the pre-nup becomes mingled in the marriage. You can't use a prenup to retain full ownership of the house you both live in, for example. It becomes community property.
You can only use a prenup to protect separate holdings that are never used in the marriage.