The PCMechanic crew goes over exactly why you should really have an UPS on your PC. I know that I couldn't live without mine... I live in the sticks, & there are frequent power outages. Every machine in my house is on an UPS, including the modem & router.

"Most people notice power fluctuations only when light bulbs flicker or when there is a complete blackout. But power supply is rarely without glitches. From time to time there are surges, spikes, and brownouts -- extended periods of low voltage -- that people don't even notice. For electronic equipment even such minor aberrations can be fatal."