What saves CMOS and Life of CMOS ?Does it helpful for the computers ?

History of CMOS : 

The Motorola 146818 chip was the first CMOS RAM chip that was used by IBM Computers ,It is capable to store the data that have the size of 64 bytes.Since the system clock uses 14 bytes of RAM and left 50 byte is used for storing system settings.

Life Of CMOS Battery: The standard lifetime of CMOS battery approx 10 years.Its also dependent on the use of computers

About The CMOS : Do we know the stand for CMOS ?

Answer is Definitely "Yes" that is Complementary Metal Oxide Semiconductor.
Its a physical parts of the motherboard , its similar a chip that is circulated with the help of battery.Its store the computer information when your system in shutdown mode.Just for information it store the system's date and time with BIOS settings ,maintain it when will you power on your system get the accurate settings of bios, date and time.Its chip technology that works on low electricity so the CMOS life have almost 10 years .

What Problem we will face ,if the CMOS failed ?
Its does not mean that if CMOS is failed , you will not able to use your system.

When we will save the setting of BIOS its save the bios setting until the reboot of your system.After failure of CMOS you will loss settings of BIOS as well as time and date

In that case you should change the CMOS battery , its not costly and its easily available in Market as well as online