Don't Get Zapped
While many of us obsess over our gear choices as if we're ordering our last meal, we often neglect to think about how we're going to protect that gear once we get it home. Even worse, many of us simply plug the system into a cheap power-strip-style surge protector, which we bought because we needed a couple of extra outlets, not because we were confident it would keep an AC surge from damaging any gear. But that can be dangerous, since power surges are common occurrences around the home.
Big appliances such as refrigerators, washing machines, and air conditioners have compressors or motors that draw lots of power and that constantly switch on and off. Those switching motors cause momentary ebbs and flows in power supplies, sucking power away from A/V equipment when the motors kick in and sending bursts of extra voltage through the system when they shut off. Even if a single one of these surges isn't strong enough to hurt your gear, over time they may gradually cause damage.
There are other potential sources for dangerous surges. The much-feared direct lightning strike will destroy any gear in its path, even with surge protection, but indirect strikes can also wreak havoc. (The only sure-fire remedy is to unplug your equipment during a thunderstorm.) Less dramatic but more common is uneven power flow coming from your local utility, which delivers electricity through a complicated maze of grids and distribution lines - all subject to failure at any moment. A downed power line from a storm (or from a careless neighbor more occupied by an incoming cellphone call than by his driving) can cause an outage, followed by a significant surge when power is restored. And even the growing number of smaller household appliances equipped with small switching motors can take their toll on the consistency of the power running to your wall outlets.