Anywhere you have "unreliable" electricity or electricity that could be better. I think in most cases, this occurs in rural areas compared to the far heavily populated suburbs and cities who provide the economics to maintain and upgrade power services (although some large cities have a notorious neighborhood or two). Having lived just about all over the Los Angeles area, we just have very good quality, reliable power just about EVERYWHERE around here (both LADWP and SoCal Edison), but my dear relatives in rural America don't! Of course, Edison is expensive (and we rate payers are going to bail out Edison for the fiasco at San Onofre, and LADWP has billing nightmares, but with very few exceptions, the electricity is always there, extremely consistent in frequency and voltage and clean and with only exceedingly rare instances of bad electricity. One such instance was when Edison did not notify customers, especially the commercial customers, that they were going to perform major work during business hours. There was a surge and it destroyed an untold number of PC's and other devices through out. Had we known our Facilities manager and IT people who have taken precutions, such as shutting everything down or just closing for the day to avoid the risk. Sometimes we can't escape being a victim of a power company.
If you are not experiencing problems now, and if your power company (private or public) is a good one, then conditioning might seem as an unnecessary expense. However, most of the good (and most of those recommended on this forum) UPS's also provide such conditioning along with being a UPS, so no real additional expense and you get the protection as a bonus. These are referred to as "in-line" UPS. Good luck.
