As much as I've liked the company of coworkers and been friendly with them, I've never had a coworker friendship 'stick' after they or I leave for very long.

The longest was a guy I used to meet up with at dog parks so our dogs could play together, or meet for a pint sometimes, and even that is looking like it's probably not going to stick.

The longest lasting friendships for me have been friends with a shared hobby. Like I have a lot of friends that are really into board games. Except for the pandemic it's been real easy to maintain those friendships, just organize a game night.