Recently, a man stepping off a curb near my office was struck and killed by a passing bus. Only 49, he clearly had many productive years ahead. Reading about it reminded me how quickly unexpected accidents can turn your family upside down, and how vitally important proper planning is.

No matter what your age, you should have already drafted a will and other key documents that outline how you’d like your financial and health matters to be handled if you die, become disabled or fall seriously ill. Even if you already have such documents in place, however, it’s important to review them periodically, particularly if your financial or family situation changes – say you get married or divorced, have a baby, a beneficiary dies, etc.

Among the things that could go wrong if you haven’t made your current wishes known:

• Court-supervised probate could hold up your estate and result in costly fees.
• Your ex-spouse might still be named primary beneficiary of certain assets.
• The state usually awards assets to surviving spouses, children and other relatives, so friends and favored charities could be passed over.
• With no will, the state decides guardianship for minor children if both parents die.

Here are a few documents to consider for preventing these scenarios:

A will declares who should receive your assets, chooses an executor to handle your estate and names a guardian for your minor children, among other decisions.

A revocable living trust creates a trust to which ownership of your assets is transferred. As trustee, you control the trust and as beneficiary, you own its assets. After you die, assets are transferred to your successor beneficiaries (heirs) without having to go through probate.

A financial durable power of attorney specifies who has legal authority to pay your bills, manage assets and conduct other financial matters if you become incapacitated.

A healthcare durable power of attorney assigns someone to make your medical decisions if you’re unable. Be sure to pick someone who would closely follow your wishes and can make tough decisions.

A living will instructs doctors and hospitals which medical treatments and life-support procedures you do or don’t want. Have your doctor put a copy in your medical file.

There are a few additional considerations for any of these documents:

• Sign, date and notarize them and file for safekeeping.
• Compare will or trust beneficiaries to those named in your insurance or retirement plans to eliminate conflicts.
• Before naming an executor or power of attorney, make sure they are up to the task.
• Name alternate beneficiaries and executors in case anyone dies before you.

Do-it-yourself kits like Quicken WillMaker Plus are available, although you should probably have an attorney who specializes in estate law review your documents. And if trusts, complex estates or large assets are involved, definitely hire a professional – one typo or skipped signature could end up costing far more than the lawyer’s fee.

Free or low-cost legal assistance is often available for lower-income people. A few helpful sites include LawHelp.org (www.lawhelp.org), Legal Services Corporation (www.lsc.gov) and the American Bar Association (www.abanet.org under “Public Resources”).

My motto: Hope for the best, but plan for the worst.

Jason Alderman directs Visa’s financial education programs. To Follow Jason Alderman on Twitter: www.twitter.com/PracticalMoney

The concerns over the high costs and long delays associated with Probate are often central to the discussions over why living trusts are far superior to wills as estate planning tools, even for relatively small estates. For strictly probate avoidance purposes however, a living trust may not always be needed. Most states have a minimum asset threshold before probate becomes mandatory, and for those falling under the line, a formal probate is not usually required.

For example, if you live in California and your estate holds no real estate and the total value of your assets is less than 100,000, then your estate will probably not need to go through probate. This threshold is usually much lower in other states though, often in the neighborhood of $20,000 to $50,000. If this is your situation, then you should at least create a will with an attorney and consider making individual beneficiary designations for your accounts at the bank.

Most of us would agree that probate should be avoided if at all possible. This is not, however the only reason a living trust surpasses a will. In my opinion, the only true benefit of having a will is having a plan in place for the distribution of your assets at death. This is all a will can do for you but is only half a plan. A better plan also has a strategy for dealing with; your incapacity, the care and support of minor children and/or grandchildren, beneficiaries with special needs, or beneficiaries with severe lack of financial acumen or maturity. Remember that a will can only go into effect after you die and cannot help you in these important areas.

Suppose you and your spouse bought a home. If you are like most of us, you need two incomes to be able to pay the mortgage. Then suppose that your spouse gets in a terrible accident that leaves him or her incapacitated. They can’t work any longer so their income stops. A will won’t help you because your spouse is not dead. Your life insurance policy won’t help you for the same reason. You decide you need to sell the house but both spouses are on title and any sale or refinance of your property will require both signatures. If your spouse is incapacitated, then you are likely to have to go to court and spend $5,000 to $10,000 to have your spouse declared legally incapacitated and have the court appoint a conservator. Then, the judge will let you know if you may or may not sell the house, and what you may or may not do with the proceeds. A properly prepared living trust will allow you to almost immediately take the actions you feel are in the best interest of you and your spouse, without interference from the courts.

Providing for your children is usually the most important goal of your estate plan. Do you have children who are minors or not yet mature enough to handle the estate you are about to leave to them? In most states if you have a will, or use the generic will that the state imposes when you don’t, your children must receive their inheritance when they turn 18. Do they have the maturity and experience at that age to be good stewards of your estate? With a living trust you can set a more appropriate age for them to have access to or manage your estate (e.g. age 25 or later). You can even set parameters for them to earn the right to receive or manage their inheritance. During the “maturation” years, your trustee is empowered to provide for your children’s health, education and welfare. If minor children survive you, a will generally leads to a strict court-ordered and supervised guardianship of your estate until your children turn 18. These arrangements are costly and restrictive, and again, your children must receive your entire estate at age 18. With a living trust there is no need for the court to get involved. Your trust would stipulate how and for whose benefit your assets were to be used, and would grant full legal power and authority for your trustee to carry out your wishes.

Remember to use a qualified attorney to make sure your will or trust is properly prepared. Avoid generic “do it yourself” kits and form books. They can’t and don’t address every family’s unique needs and can be disastrous in the end.