When I adopted my dog, I was living alone and knew that he'd be in danger if anything happened to me (e.g., hit by bus), as it might take a few days for anyone to notice.

To handle such a scenario, I built a service to check on me and notify my contacts if I went missing. i.e., a "Dead Man's Switch".

Pretty neat! I've long had the idea to build dead man switches into various things that I've set up mostly as a way of cleaning up after myself to prevent bitrot from degrading things, and also probably out of spite, but I've always been too lazy.