Do you ever think about writing a "open in the event of my death" letter?

I don’t mean a suicide note, I mean a letter just in case you get hit by a bus tomorrow. The type that says all the things you haven’t been able to bring yourself to say or contains things like your internet passwords and requests that people like fellow Jellies (that wouldn’t necessarily be informed) be informed.
On a related note, where would you keep it and what would you label the envelope?