Is your estate plan in good shape? Here's what to consider.

Most Americans don't have a will, to say nothing of a more comprehensive plan to avoid probate or save on estate taxes. Do you need to start planning what happens to your estate when you die? It depends on your age, health, wealth, and innate level of caution.

Many people don't need to do much in the way of estate planning. And even if you do decide you need a will or a trust, you probably won't need a lawyer. It is easy and safe to prepare most basic estate planning documents yourself. Just learn what you're doing by using good explanatory materials.

We've sorted our tips into broad categories of family situation and age. But keep in mind that age is an imprecise proxy for life expectancy, which is affected by all sorts of other factors -- heavy smoking while participating in extreme sports and driving a motorcycle, for example. It's up to you to add or subtract a few years, based on your health and lifestyle.

You're 25 and Single

At your age, there's not much point in putting a lot of energy into estate planning. Unless your lifestyle is unusually risky or you have a serious illness, you're very unlikely to die for a long, long time.

If you're an uncommonly rich 25-year-old, though, write a will. (Bricks can fall on anyone.) That way you can leave your possessions to any recipient you choose -- your boyfriend, your favorite cause, the nephew who thinks you're cool. If you don't write a will, whatever you leave behind will probably go to your parents.

You're Paired Up, But Not Married

If you've got a life partner but no marriage certificate, a will is almost a must-have document. Without a will, state law will dictate where your property goes after your death, and unmarried partners get nothing. (The only exceptions are the states where you can go through a civil union or register as domestic partners; in those states, surviving partners can inherit just like surviving spouses.) Instead, your closest relatives will inherit everything.

Another option to make sure that your partner isn't left out in the cold after your death is to own big-ticket items, such as houses and cars, together in "joint tenancy" with right of survivorship. Then, when one of you dies, the survivor will automatically own 100% of the property.

You Have Young Children

First, write a will. Nothing fancy, just a document that leaves your property to whomever you choose and names a guardian for your children. The guardian will take over if both you and the other parent are unavailable. If you fail to name a guardian, a court will appoint someone, possibly one of your parents.

If you don't have a will, some of your property may go not to your spouse, but directly to your children. The problem with the children inheriting directly is that the surviving parent may need to get court permission to spend or invest the money -- a waste of time and money in most families.

Second, think about buying life insurance to replace your earnings if that damn brick chooses you. Term life insurance is relatively cheap, especially if you're young and don't smoke. You can shop for the best bargain online, by consulting free services that compare the rates of lots of companies.

You're Middle-Aged and Know the Names of at Least Three Mutual Funds

This is the time when most people consider estate planning in earnest. Keep in mind that your assets and what you want to do with them may change in ten or 20 years -- be prepared to revisit and change your estate plan accordingly. Here are some estate planning options:

Revocable Living Trusts

To save your family the cost (and hassles) of probate court proceedings after your death, think about creating a revocable living trust. It's hardly more trouble than writing a will, and lets everything go directly to your heirs after your death without taking a circuitous and expensive detour through probate court.

While you're alive, the trust has no effect, and you can revoke it or change its terms at any time. But after your death, trust property can be transferred quickly, according to the directions you left in the trust document.

Payable-on-Death Accounts

There are other, even easier ways to avoid probate: You can turn any bank account into a "payable-on-death" account simply by signing a form (the bank will supply it) and naming someone to inherit whatever funds are in the account at your death. You can do the same thing, in almost every state, with securities.

Take Steps to Reduce Estate Taxes

If you have enough property to worry about federal estate taxes, think about tax avoidance as well. Currently, estates worth more than $2 million are taxed; that amount is scheduled to increase in future years. (The estate tax is being phased out, but its future is uncertain. ) If estate tax does take a bite, it can be a big one: 45% of everything over the exempt amount. Here are some ways to reduce estate tax: