What happens when CMOS battery fails

It is not that the computer will stop working when the CMOS battery is exhausted, no, whenever we change the BIOS configuration of our computer and save, those settings will be present in the CMOS chip only as long as the CMOS chip gets power. But as soon as the computer is restarted, those settings will be reset to the default because when the computer was off, the CMOS could not supply power due to a battery failure and the BIOS setting was reset to the default, so the CMOS battery should not drain more time than this. Other functions like Date, Boot Device Priority etc. will be reset.