Time to replace the UPS?

I have an APC Smart-UPS 3000 RM XL made in 2005, which I got off eBay in 2015. It served me well through couple sets of batteries and (admittedly few) power outages over the years. In the past three weeks however it bounced the load side several times, rebooting my servers. My microwave didn't lose the time, so I am pretty sure there was no utility power blip, it just appears to have done it out of the blue. The UPS's logs have nothing out of the ordinary. The last self-test is "OK". Is there something that I can easily check and possibly fix? Or is it time to replace the poor thing? If it is time to replace, what would be a similar unit? (the APC is 3000VA, which I don't need per se, but I do like ~1hr of runtime it promises being loaded at 15%. I also like that it's networked, and 3U of rackspace is fine. Oh, it's also in the basement, so noise is not an issue. The budget is several hundred $, so presumably something used off eBay?)