People entering this post may enjoy Larry Niven's short SF story 'Grendel' in which, if I remember correctly, the protagonist solves a murder partially by reali

People entering this post may enjoy Larry Niven's short SF story 'Grendel' in which, if I remember correctly, the protagonist solves a murder partially by realizing that a female antagonist was actually much older than she appeared, due to using an immortality drug, and that the need for novelty was a driver for such people.