Do you have a will? If so, you're off to a great start when it comes to estate planning. A will is legal document that allows you to distribute your assets to your heirs in nearly every manner you see fit. A will is also your last chance to express your wishes, so it can help diffuse any family disputes that may arise after your death. However, as important as a will can be, there are still some things that it can't do. Depending on your situation, you may need additional estate planning documents above and beyond a will. Here are four situations in which a will is of little use:

Passing on assets that have a beneficiary designation. Assets that have beneficiary designations cannot be controlled by a will. These assets include things like life insurance, annuities, 401k plans, pensions, and other qualified retirement plans. You list one or more beneficiaries on each of those assets and that designation is what guides the distribution of the funds. Also, payable-on-death and joint tenancy bank accounts are in the same boat. If you want to make changes to the way they're distributed, you'll need to change the designation on the specific asset or account.

Stating funeral wishes. Do you have specific wishes and plans for your funeral? Planning ahead can take a lot of stress off of your family. However, you'll want the instructions to be in a place that your loved ones will immediately notice. A will isn't the place for that. Very often, wills aren't read until weeks after someone dies. At that point, your family will have already had the funeral. Instead, create a separate funeral planning document and tell someone you trust about its existence. Make sure they know where to find it in the event of your death.

Arranging financial care for minor or special needs beneficiaries. You can use a will to specify who will take guardianship of a minor or special needs dependent. However, a will can't be used to setup any kind of financial management plan. You could leave money to the new guardian, but there's no guarantee that the guardian will use the funds for the dependent's benefit. Instead, you may want to set up a trust that states how those funds can be used and when they can be passed along to the minor.

Leaving money to a pet. Contrary to popular belief, you can't use a will to leave money to your dog. A dog is property and property can't be a beneficiary. You can leave the dog to a trusted friend or family member and then leave money to the individual for the care of your dog. Alternatively, you can set up a trust for the dog's care and leave money to the trust. However, wishes in a will for money to go to a pet are likely to be ignored by the court and executors.

For more information on what a will can and can't do, contact an estate planning attorney (such as Acton & Snyder, LLP) in your area. He or she can review your situation and advise on whether you need additional documents.