To determine the longevity ompartments there are methods prescribed by the sages. We would discuss the same in this article

1)Method of 3 pairs

2)Eight lord placement

3)Method of 3 lords

First let us see the Method of 3 pairs:

This method is based on the 3 pairs of signs which includes the sign occupied by the lagna lord and the 8th lord 

The lagna and Hora lagna

Moon and Saturn

When talking about signs all the 12 signs starting from Aries to Piesces have some energy in them. Aries has Movable energy,Taurus has fixed energy and Gemini has Dual energy and so on.  All Movable signs are controlled by Bramha the creater hence long life is indicated, All fixed signs are controlled by Shiva the destroyer hence  short life and finally we have have  dual signs which are controlled by Vishnu and indicates middle life.  Long life compartment is 72-108,Middle life 36-72 and Fixed life 0-36..

When calculating longevity if any two pairs indicate the same compartment then depending on whether it is long.short,middle life that life compartment coms into existence.  For ex: if we get Movable+Movable+Fixed after calculating the longevity compartment then the native life compartment can be told as Long life, and if we get Fixed+Fixed+Movalbe then it would be short life and if Dual+Dual+Movalbe then it would be middle life.

If we get Movable+Fixed+Dual longevity compartment then we need to consider the pair of lagna+Hora lagna.Else if we find that Moon is in the 1st or 7th house then the compartment connected to Moon+Saturn pair has to be taken.

Eight lord Placement:

Take the strongest between the 8th house lord from the lagna and 7th house which is the 2nd and 8th house. The stronger between these two lords become rudra.  If this rudra is placed in the quadrant(1,4,7,10) then it is long life, succedent(2,5,8,11) then it is middle life and precedent93,6,9.12) then it is short life.

8th lord is placed in any of the above places then depending on the placement the life compartment can be defined

Method of 3 lords:

Here we need to take the placement of the lords of the 1st,10th and 8th house and also Saturn. If all the 3 lords are nicely plaement in 1,4,7,10 then long life is indicated, if 2 lords are placed in quadrant then middle or else short life is indicated. If none of these are well placed in quadrant then very short life is indicated

After calculating the life compartment we need to narrow done using Shoola dasa. As per this the following should be considered:

1)Malefics in a sign would make it strong to kill 

2)A  malefic sign is capable to killing the native

3)Aspect of Malefics on a sign is stronger of the above two

4)Sign occupied by Rudra or its trines would kill the native

5)Sign occupied by Sthira Karaka(natural significators) or its trines, 8th lord from it or 8th lord from Arudha lagna

6)Sign occupied by Maheswara would also kill

7)sign occupied or aspected by Moon/Venus/Mars can kill.

Example chart of Swami Vivekananda:

Date of Birth:12th Jan 1863

Time:6:33 AM GMT

22N40 88E30

Method of 3 Pairs:

Lagna lord + 8th Lord=Jup(Movable) + Moon(Dual)=short life

Lagna + Hor lagna=Saggitarius(Dual) + Capricon(Movable) =short life

Moon + Saturn = Virgo(Dual) + Virgo(Dual) = Middle life

Here we see that short life is dominating.  But Sun is in lagna and being Atmakaraka the life compartment has increased from short to middle 36-72 Years. Here we find that Moon the lord of the 8th house is placed in quadrant indicating that his life compartment should be 72-108 but saturn being placed there has brought down the life compartment to 36-72..

8th lord Placement:

8th lord Moon is placed in the 10th house indicating a long life but as mentioned earlier it is with Saturn changing the life compartment from 72-108 to 36-72 Years

Method of 3 Lords:

Lagna lord is placed in 11th house

8th house lord is placed in 10th house but afflicted by Saturn

10th house lord is Mercury being placed in the 2nd house

Hence out of the 3 we find that 2 are fairly strong giving the life compartment between 36-72 Years

Eight house lord from lagna should be seen for checking which quarter of the longevity compartment is applicable.  If lord of the 8th house from lagna is placed in 10th,11th and 12th house hence it would be in the first quarter, if 8th lord house is placed in 7th,8th and 9th house then it would 2nd quarter and if placed in 4th,5th and 6th house it would be in 3rd quarter else in the 4th quarter

Life compartnent for Swami Vivekananda is 36-72 as per the caculations already mentioned.  Here we find that the 8th lord from Lagna is in the 10th house hence it would be first quarters of life compartment which is between 36-45 years.  One quarter is of 9 years hence when we add 9 to 36 years we get 45 years which can be taken as 36-45 years.

Swami Vivekananda passed away during hs 40th years The dasa's operating of Seamiji during his death was Jup-Ven-Saturn.

The Maraka houses from his lagna are Capricon and Gemini which means Saturn and Mercury can decide the end.  

Dictum:

Lords of the 2nd and 7th house,planets conjoining these plants or planets placed in these house would become marakas. We find the 2nd house from lagna of Vivekananda is Capricon whose lord is Saturn and 7th house house is Gemini whose lord is Mercury. Mercury has conjoined the 2nd house. But here the first maraka planet which operates would decide hence Saturn  which is the Pratyantara dasa lord operated and became maraka

Greatful to all my gurus (Sanjay Ji,Rafal Ji and Visti Ji) for guiding me through their books and blessings in learning this subjects