Thanks for the replies. How do I know what "size" UPS to buy? There are so many options...
It usually depends on how much backup power time you want/need when the power goes out. Most home studios need enough time to simply save work and shutdown all their gear. IOW....you're not going to keep on working for too long when the power goes out. Also...the more gear that is on the UPS, the faster it drains the battery...which will need to be replaced every couple of years, depending on how often it has to do backup duty.
The better surge/power conditioners protect your gear more than a basic UPS will, which is mainly for power backup (though there are some hefty UPS units that have good protection too).
One thing though, most UPS units don't put out the proper, pure AC sine wave (there's only a few top shelf models that do) ...which may not be a major concern, but it can have some effect on audio hardware....pres, comps, amps, etc....
...I mean, if you are really looking to improve things.
Here's some info:
When do I need a pure sine wave UPS?
Deciding what's necessary is a personal choice. I would consider how much your power fluctuates or has brown/black-outs...also a power level/spike meter (you can get the power company to do a 24 hour meter) will tell you have steady your power is, and if there are any spikes. Not to mention that you get the benefit of cleaner power.
Personally, I would always run a decent power conditioner/surge/spike protector in front of the audio gear. Put a good UPS in front of the computer.
Furman makes some good power protection/conditioning, balanced power and voltage regulation gear.
I've got a fairly large amount of gear, so my concerns are a bit greater. I run one main 20A power surge/power conditioning box, and then that feeds a 20A voltage regulator box that also has another layer of surge/spike protection, and that feeds my entire studio, and then a UPS for the DAW & monitors.
I've thought about adding a balanced power unit after the voltage regulator....but they are pricey, and I always seem to have other studio toys on my priority list.
Generally speaking, I don't have a lot of power issues, though my power always runs on the high-side limit of 125V, but there was one time where we had a brown/black-out, with rapid on/off...and it fried my TV, my micro, and my phone answering machine (of course, none of that stuff is connected to my power protection gear).
So all it takes is one time, and you could kill a couple of pieces of gear.