I agree this is a good practice. I bought one primarily to allow me to continue to use my laptop even when a.c. power is out. I have a cable-TV connection that continues to operate off independent power when commercial power goes off. My 650 v.a. UPS unit powers my cable modem and WiFi router for almost 4 hours. If I plug my entire desktop system in, it runs for about 10-15 minutes before the battery goes dead... not really enough to do useful work, but long enough to do an orderly shutdown. Cost was about $75.