In 2007, Kevin Kelly started displaying a life expectancy countdown clock on his computer. (I posted about it on Boing Boing.) Here's what he wrote about it:

I've been using this system for several months now and it has been very powerful. Day to day I am aware — and can rattle off if I am asked – how many days I have left. I decided to post my project today because on my clock it shows a handily rounded off sum. So here is the news: As of today I have 8,500 days left to live. That's not much in my book. I can almost hear them ticking away as we speak. I look at my lifelist of current dreams and I realize that in only 8,500 days I won't get to but a few of them. And what of any new dreams?

(It must be at 6,500 or so now.) I thought of Kevin when I saw this 1991 patent for a "life expectancy timepiece":

It shows the years, days, hours, minutes, and seconds you have left, according to actuarial data. I think Kevin's "days remaining" presentation is more moving than this watch's display, however. Someone should Kickstart a wristwatch that shows how many days you could expect to live!

Memento Mori