Vimshottari Dasha assumes that the maximum duration of life of a person is 120 years which is the overall duration of all nine planetary periods i.e. Ketu 7 years, Venus 20 years, Sun 6 years, Moon 10 years, Mars 7 years, Rahu 18 years, Jupiter 16 years, Saturn 19 years and Mercury 17 years, in the order of their operation.