Why should we use numerology?

The day we are born, our birth date number rules us & gives us all the related vibrations. The day we get a name we start getting another vibration (the number we derive by adding the total of the name spellings). It is important that the name vibration should match with the birth date vibration for harmony, growth and positive approach towards life. As changing our date of birth is not possible, so alphabets are added or subtracted to a name to match it with the vibration of our birth date.