This piece of research popped up unbidden into my work inbox today and I thought it may be of Languish interest. Precis: When statistically modelled, the length of time from the beginning of their reign until their death followed a set pattern, similar to that seen in reliability engineering. Time to failure of your emperors may vary.
https://www.eurekalert.org/pub_releases/2019-12/s-tor121819.php (https://www.eurekalert.org/pub_releases/2019-12/s-tor121819.php)
How many died in the bathtub?
Heh it would be interesting to see what combination of personality and acts would be considered "functional" for a Roman Emperor over the course of history.