Movies and pop culture often depict prenuptial agreements as protection for wealthy old men from gold-digging trophy wives, but the reality is that prenups are simply a useful financial tool, especially for those entering second marriages.

You should consider a prenup if any of the following situations apply to you or your future spouse:

• You have large income or re disparities. In a marriage, property and income usually become community property, even if held in one person's name. Mapping out what property belongs to whom makes it easier to divide res in the future, should the couple divorce.

• You have children to whom you want to bequeath heirlooms, parts of your property or even a stake in a family business. A prenup will ensure that your children's inheritance goes to your children should you die, or stays in the family in case of divorce.

• You are bringing debt into the marriage. A prenup can protect your future spouse from any debt you have racked up (or vice versa). If you divorce or if one partner dies, a prenup can protect your spouse from being liable for the debts you brought into the marriage.

• You want to keep your finances separate. A prenup allows a couple to keep their finances separate and protects against individual property becoming community property.

• You own property on which other family members depend. People often buy property to support aging relatives or invest in property for adult children to live in while they are in school. If you own the house that your parents or your children live in, you will want to protect your family members as well.

Creating a prenup can be simple or complex as the laws vary from state to state. For example, in the state of Virginia, a couple needs only to draft and sign an agreement, and it becomes valid once the couple is married. The premarital agreement doesn't even need to be filed with a court; it can just sit in a drawer in your home.

If you're not comfortable with drawing up a prenup yourself, you can always seek professional legal help. You can choose to have an attorney for each spouse, but one will also work just fine. After all, you are making an agreement to enter into a marriage, and this is a good time to practice the art of compromise and caring.

Remember that a prenup is a financial tool; therefore, it can include nearly anything regarding your finances – details about who pays the bills, agreements to save money together and how you will file taxes. In some states, a prenup can prevent any future alimony payments, but this differs from state to state.

A prenup cannot touch child support, visitation rights or custody. Additionally, since a prenup is a financial tool, it cannot be used for non-financial matters. You can't make your spouse promise to make lasagna every Friday, for instance. And you can't use a prenup to designate who will change their name or to make agreements about children.

In order for a prenup to be valid, each party must prove full financial disclosure. That means no hiding assets or sweeping debt under the rug. Retirement plans, insurance policies and even expected inheritances – if you have information about a wealthy relative's estate plan – all must be disclosed ahead of time. Otherwise, the prenup may be considered void in court.

Additionally, a prenup must be considered conscionable – that is, fair. This may be decided by the court in case of divorce, but keep it in mind as you draft your paperwork.

Two more obvious notes for a prenup to be legal: You both must voluntarily agree, and your marriage must be recognized as legal by the state. (For more, see Top Tips for Implementing a Prenuptial Agreement.)

While you're busy mapping out your property and potentially consulting with lawyers, this is a good time to get your estate plan in order. Many of the same details that you consider while drafting a prenup are required for an estate plan, and this is a good way to ensure you are providing for your spouse and managing your children's inheritance at the same time. (For more, see 6 Estate Planning Must-Haves.)

If you didn't make a prenup but are thinking that it would have been a good idea, you can still make a postnuptial agreement! While a postnup is considered less valid than a prenuptial agreement, some legal documentation is better than none. (For more, see Benefits of Prenuptial and Postnuptial Agreements.)

Prenups may get a bad rap, but they are a useful financial tool developed to protect yourself, your future spouse and your family. As such, they should be considered anytime a couple is bringing significant assets or debts into a new marriage.

See also: Before You Remarry: Blending 2 Families' Finances.