You may well have invested several thousands of dollars in the computer and stereo equipment in your home. One additional - but necessary - expense is a surge protector which can help protect not only the equipment itself, but photographs, documents and other irreplaceable files. And you don't want your expensive home theater system to be damaged by a power surge either.

So why exactly does your home need a surge protector? Over the last few years, most electronics have become increasingly sophisticated and as a result, they can be damaged by just small surges in voltage. These occasional small surges can have a cumulative effect over time and cause damage not only to a computer, but televisions, modems and stereo equipment. And a huge power surge can instantly damage computer, stereo and TV equipment.

Power surges are most commonly associated with storms and lightning. Lightning actually strikes somewhere in the world 100 times every second and there are an estimated over 100,000 storms every year in the United States. Annual figures for property damage caused by storms routinely runs into billions of dollars - and if you live in the States of Georgia, Florida or the Carolinas, you are particularly at risk from power surge damage caused by thunderstorms and lightning.

Power surges can also be caused by strong winds and ice storms, or by power lines being brought down by heavy snow. And if your neighbors are for some reason using an extra amount of electricity, it can cause a power surge in your home - it's common for power surges to occur on hot days when everyone is using their air-conditioning to its maximum.

Surprisingly, an estimated 70% of power surges actually originate inside the home - if you have ever experienced a brief flicker on the TV or lights, it's probably caused by a power surge. They can also be caused by such things as turning on a major appliance such as washing machine, dryer or air conditioner. The extra electricity suddenly being used creates a brief surge that can affect the wiring in your home.

And power surges can be caused by faulty wiring, an overloaded circuit, faulty circuit breakers or a poorly grounded appliance or wall outlet. A surge protector is a must if you live in an older home - or if you suspect that the wiring in your home may not be in the best condition. While we may have some warning of an approaching storm, a spike in voltage on a power line generally occurs without warning.

And try to make sure that your surge protector protects against lightning strikes - not all of them do. The type of surge protector you need will also depend on the modem that you have - if you have a regular modem, choose a surge protector with a phone jack; if you have a cable modem, you should choose a surge protector that will also accommodate TV, cable and internet connections.

Surge protectors come in two basic types - a power strip that allows several different appliances to be plugged in, which also doubles as a surge protector. You probably have all of your computer or home theater equipment plugged into a strip containing several outlets. Be careful as not all power strips offer surge protection. Fuses and circuit breakers don't protect against surges in power either.

Power strips are also convenient, in that they allow you to have everything plugged in to a central location. You can even label the plugs, so you don't accidentally pull out the wrong plug - easy to do when half a dozen things are plugged in. And with a power strip, there is also no danger of overloading the outlet.

You can also purchase what is known as a whole house surge protector. These devices usually connect to your circuit breaker panel and protect every device and fixture in your home - they generally cost between $200 and $600. If you aren't comfortable installing it yourself, an electrician can easily do it for you.

Your property insurance or homeowners' insurance may not cover damage or loss due to a power surge. Even if it does - you may be faced with paying a deductible of up to $500. Typically, a good quality surge protector offers primary coverage - this means that you don't need to claim through your property insurance first. Make sure that the warranty that comes with the surge protector covers not only the device itself, but any equipment connected to it as well.

An adequate surge protector is inexpensive, costing as little as $20. Its well worth the money for peace of mind and the insurance it provides.