Too many Floridians returning home from Hurricane Frances are about to discover there's something worse than losing their home -- not enough insurance coverage to replace it.

It's a discovery, unfortunately, that's all too common.

After Southern California's 2003 fire storm season, one-third of the victims didn't have any homeowners insurance and another one-third were underinsured, according to California's Department of Insurance.

Risk analysis company, AIR Worldwide of Boston, estimates that many upper-income homes in New England are underinsured by 30 percent to 40 percent.

Los Angeles, CA-based Marshall & Swift/Boeckh, which assists insurers with calculating the value of houses, estimates that 64 percent of American homes are underinsured by an average of 27 percent, with some homes underinsured by 60 percent or more.

And nationally, approximately 75 percent of structures in flood-prone areas do not participate in the National Flood Insurance Program and, as a result, are uninsured against flood risk, according to the Insurance Information Institute (III).

Why homeowners don't take the steps necessary to adequately insure what's likely their most valuable asset is often a mystery, but experts surmise it's not always the homeowner's fault.

Many homeowners who held homeowner insurance policies for years don't know that since the late 1990s they have to specifically ask for a "guaranteed replacement policy," or insurers may only issue, at best, an extended replacement policy which sets payout limits plus an extended 20 to 25 percent additional payout, which still may not be enough to cover the cost of rebuilding a destroyed home today.

The nation's housing and remodeling boom has driven up the cost of building materials and that cost typically rises even more after the additional demand generated by natural disasters like Florida's recent hurricanes and California's wildfires.

Likewise, booming home sales has driven up the price of existing homes and if you purchased your home a few years ago your insurance coverage is probably tied to that outdated sales price.

However, homeowners are ultimately responsible for making sure they have adequate coverage.

The institute says there are four major events that should trigger a review of your policy:

1. When it's time to renew your policy check your coverage.

   Consumer Reports offers access to Salt Lake City-based Castle Data's Replacement Cost Calculator. Non-Windows computer users, Windows users with old browsers and anyone who wants a more detailed analysis can opt to use Building-Cost.Net's more sophisticated calculator.

   Also, shop around for the best rate, consider reducing the deductible to save money, ask your agent about any policy changes, seek specific coverage for hurricanes, earthquakes or flooding; check your liability and personal possessions coverage; and inquire about any discounts available.

2. When you make a major purchase, build an addition onto your home or improve it, talk to your agent about increasing the coverage to cover the additional square footage, added property value or the value of the purchase.

3. If the improvement makes your home a safer home you may qualify for a discount. Fire alarms, sprinkler systems, burglar alarms and upgrades to heating, plumbing and electrical systems may qualify for a discount.

4. Marriage, divorce, new kids, kids leaving for college or returning to the nest can require insurance coverage changes as possessions also come and go.

Finally, keep your policy in a safe place, preferable away from the home, say in a safe deposit box. Store it with an inventory and purchase receipts for your possessions. Video taping or photographing your belongings provides strong evidence of what may need to be replaced.