[greenpeas]

What is your heuristics based on?

Quite often though, you know a little about some thing. How do you adjust your heuristics then? What about the job that I started two months ago, should I expect to work there by December 2023? If the US was founded in 1776, how long will it still exist?

[vcxy]

The heuristic is that the average of an interval is the middle. If you know nothing about it other than you're at some point on the time interval, assuming you're at the middle time is a good prior.

When you know more, you certainly should adjust. For the job example, you might think "how long have I usually stayed jobs that have lasted least two months?", "how long do people usually stay in jobs if they make it through the first two months?". Generally speaking, Bayes' theorem is the technical answer to "how do you adjust". Not that I ever actually do that...but I think it's the technically correct answer.

[Bilal_io]

Not OP and haven't read the book, but maybe this is more about survival, if McDonald's survived 82 years, then we can assume it can survive another 82, if you've been at the job for 2 months and there are no signs of trouble, then you can assume you'll survive another 2, reevaluate then to conclude that you can survive another 4...