Seriously, there isn't really a lot you can do.
To begin with, I would say only upgrade if it is needed such as you have a critical problem or it offers something you need - if it just changes a logo or adds a feature you will never need, there is no point in doing it.
Backing up really isn't an option on most, and when you upgrade, it could make the saved profile no longer work.
I would say, if you are constantly having power cuts, don't do it - and on the same topic, it doesn't hurt to have a UPS on your machine as best practice, but it isn't worth getting one just for this!
I would say, just go for it - some modern machines offer the ability to back up the BIOS and recover in the event of an error. If however you don't have this option, make sure you have access to another machine so that you can download a recovery image or emergency image (different names across different manufacturers) so you can do a recovery if needed.
This being said, I have had power cuts and problems and sometimes it still works - there is no one answer fits all and it changes from manufacturer to manufacturer.
Hope this helps!
In addition, a piece of advice as I just upgraded mine (GPU Voltage change, stops freezing!), Write down as many settings as you can, especially every one you changed. After upgrading my BIOS(well... EFI), made Windows not start and BSOD. The reason was because my default setting was
SATA Mode to
IDE, when I had changed it to
AHCI. Changing it back after flashing made Windows boot normally.
I would also say, it is sometimes best to perform a settings wipe / go to defaults upon a flash and then change settings back just in case there are any conflicts or settings left over that have changed or similar.