to be honest, we typically don't run heaters at all, unless the tank is chilled and then the heater is actually controlled by the internal temp controller of the chiller. we do this to minimize fluctuation.
it really depends on how cool your home gets during the winter. if it drops lower than say 75*F, you might want to consider one, depending on what you keep. remember that your lights, pumps, etc all contribute to the tank's 'inherent' temperature, so there is usually SOME heating anyhow.
also, you can also use it in conjunction with a tank controller (RK, Neptune, etc.) or a single-stage temp controller. either of these will serve as the thermostat, so even if the heater contacts stick "on", the heater won't run away with itself.
lastly, another thing you can do is unplug the heater in the summertime when it's not needed, which minimizes the risk since the heater isn't receiving power.
HTH