Length of life is one of the oldest problems in astrology and one of the most heavily hedged. Ptolemy gives it a long chapter in the third book, built on a prorogator, the point that gives out the life, and a destroyer that ends it; the medieval tradition calls these the hyleg and the anareta. The method has enough steps and enough exceptions that no two later authorities apply it identically.
That elaboration is itself a finding. A technique with many conditions is a technique whose practitioners kept meeting results they had to account for, and the length of life literature has that shape throughout its history. Bonatti in the thirteenth century and Lilly in the seventeenth both carry the method forward and both add qualifications to it.
There is also a long record of the practice being restricted. Predicting a death from a chart has been treated as improper, dangerous or forbidden in several of the periods this material comes from, sometimes by astrologers themselves and sometimes by the authorities over them. That restriction is part of the tradition and belongs in any description of it.
Modern astrology adds Pluto to the eighth house significators, taking it to rule Scorpio and to govern transformation, compulsion and what is buried. Traditional practice does not accept the outer planet rulerships and keeps Mars as the lord of Scorpio and Saturn as the significator of endings. Both positions have practitioners today, and the atlas records the disagreement rather than resolving it.
Sources TetrabiblosClaudius Ptolemy with Christian AstrologyWilliam Lilly, Liber AstronomiaeGuido Bonatti