Hi,
You should definitely replace the batteries in your Smart-UPS 1000. The SUA1000 that you show in your picture, is a great network grade UPS. This is not like the home user units such as the XS, CS, BR series of UPSs. The Smart-UPS 1000 SUA1000 is actually a network grade UPS that can provide surge protection, protection from brownouts, spikes and sags. Unlike the XS/CS/ES units, it outputs a sine wave, has AVR Boost and Drop, and provides constant clean power.
APC Smart-UPS 1000 SUA1000 Specifications
I say this to customers all the time, don't throw out a good UPS just because the batteries have gone bad. A lot of people think that the UPS has expired as well. The UPS has no moving parts inside and with fresh batteries and good care, can last many years. As another user stated earlier, he has 10+ year old symmetra that still works.
If the UPS isn't giving you any problems, you should not replace it. By replacing a good working UPS, you could be buying yourself into problems!
Make sure when you shop online for batteries that you get a good quality set of batteries. Beware of vendors who sell batteries too cheap, way below market price. There are many great vendors and a lot of shady vendors out there which sell 1 year life span batteries. So if it looks too good to be true, it probably is!
Good luck with the unit, I am sure with good batteries, it will server you well for many years to come.
Tony,
ExcessUPS
ExcessUPS.com - Experts in Refurbished APC Battery Backups & Replacement Batteries