Raspberry Pi Operating Systems are by design meant to be powered off gracefully just like others. If they are hard booted often, OS gets corrupted and the only solution I found is to reinstall the OS. This also means you will have to back up your data first.
The power supply that I use for RPi is 24 hours but it’s not uninterrupted. When electricity from pole goes off, power backup from generator takes a few seconds to start and that’s enough to cause RPi reboot.
I had this problem from day one, but a mobile/tablet power bank is the solution for it.
Since RPi has modest power requirement of 5V and 1A, the output from such a power bank meets power requirement. Now I’ve connected it between the USB mobile charger(that I had been using as power supply) and RPi.
It makes a perfect Uninterrupted Power Supply for my little computer 🙂