When many people hear the word "will," they think of a legal document that's just for "old" people, but wills are useful for people of all ages. If you are a young adult, you may want to consider a will. Here are five signs you need one.

1. You Have Children

Regardless of what age you are, if you have children, you need a will. If you don't have a lot of assets, the will doesn't need to be complicated. It simply needs to state who you want to have legal custody of your children after your passing.

You can make your own will, but to ensure that everything is done correctly and that your wishes will be carried out as desired, you may want to at least consult with a specialist or an attorney.

2. You Have Assets

If you have significant assets, you should also detail who they go to in your will. Most states have intestacy rules that come into play when you don't have a will. The rules vary from area to area, but as a general rule of thumb, your assets go to your spouse, children, and then other close relatives such as parents or siblings.

If you want the assets to go to someone who is not first in the line of intestacy, you need a will. For instance, if you have a close friend or a stepchild, in most cases, they won't get anything if you don't write a will outlining that you want them to inherit something.

3. You Have Life Insurance Policies

Your will can also be a useful place to outline who receives the payouts for your life insurance policy. For instance, you may want your children to get some of the policy, but you may want some of the funds to go to whomever is taking custody of your children after your passing. When dealing with wills, make sure that the benefactor listed on the will is the same as the person you list in your will. Discrepancies could create a mess after your death.

4. You Have a Business

If you have a business with assets, you may want to detail what happens to those assets in your will. Additionally, you may want to outline what happens to the business itself. If you have a lot of instructions, however, you may need to set up a trust. A trust is a vehicle for asset management, and you can stipulate all kinds of things with a trust. A will is just a simple document outlining who gets what assets.

5. You Have Pets

Finally, you may want to make provisions for your pets in your will. Some young adults even set up a trust to ensure that their pets will be financially taken care of after their death.