An Astrologer can only give an Indication of what promise the future holds. Only Brahma, the creator, can say with certainty what will definitely happen. This applies most appropriately to Longevity determination. Matters like longevity cannot be decided by us mortals. They are in the hands of the supreme power and an Astrologer who wishes indulge in longevity determination, needs help of this super power to make the correct judgement.