Do you need a UPS, and how long will it really last

A UPS exists to give you enough time to save your work and shut down cleanly. Anything beyond that is a bonus, and expecting hours of runtime from one is the most common misunderstanding.

Reading the VA rating

A 600 VA unit delivers roughly 360 W. A typical office desktop and monitor draw somewhere around 150 W, which puts you in the region of ten to fifteen minutes. Adding a printer to the same unit will collapse that figure — printers draw heavily and should stay on the wall socket.

What it protects against beyond outages

Sags, surges and brownouts do slow damage to power supplies over time. A line-interactive UPS regulates voltage continuously, which for many people is the more valuable function day to day.

The battery is a consumable

Expect three to five years before capacity falls noticeably. A UPS that beeps constantly or cuts out immediately on a power failure almost always needs a battery rather than a replacement.