Treat the Standalone UPS as an Emergency Backup
Set up your data center so that the standalone universal power supply (UPS) is only engaged when your rack-mounted power supply is at its limit. Any outage that lasts longer than two hours is serious, so your standalone units have to be able to shoulder the load when the primaries stop functioning.
Assign Extra Rack-Mounted UPS to Sensitive Cabinets
Add an extra rack-mounted UPS unit to any cabinet where you're hosting irreplaceable data. The extra time a second unit gives you can be the difference between a close call and a disaster.
UPS/Battery Backup Accessories: Keep It Simple
Exercise discretion when you're adding accessories to your UPS/battery backup system. Though it's good to invest in features you need, each addition complicates the setup you already have. Be sure you're getting exactly what you need, and upgrade later if necessary.