About UPS batteries dying, expect 2-3 years from a new one. That's because most UPS continue to give their batteries charging current even when they are fully charged. That's just the way they were designed. A smarter UPS design that does not cook batteries is simply more expensive to design and construct. I have solved this problem by replacing the standard gel cell batteries in all my UPS with motorcycle lead acid flooded units. Not only are the motorcycle batteries cheaper than the gel cells, they last longer. I am on their 7th year already and they are still fine. Just a few caveats: I can't install the wet cell batts inside the UPS housing so I drilled 2 holes in the back panel and connected thick "extension cord wires of around gauge 10 stranded wire" to bring out the + and - battery leads outside the unit to connect to the batteries. Wet cell batteries contain liquid acid, so there's the danger of tipping the battery over and spilling the acid on your floor. Wet cells release explosive hydrogen when charging and discharging, so you must have good exhaust ventilation in your room. Last, electrolysis depletes the water in them, so I have to add distilled water once a year to them. I use a medical syringe and Wilkins or Absolute bottled water. Another plus for wet cell batteries: Most gell cell batteries in UPS of around 650 VA are rated 7 AHrs. You get around 15 minutes of reserve power with this. Install a bigger wet cell battery, and you increase its capacity to keep your computer rig going during power interruption. Heck, you can use a car battery of 33 AHr capacity, and it can keep you powered up for as long as an hour on battery power. Just be aware that, unless it has a cooling fan inside, your UPS electronics may overheat if you go this route.