I have a friend who is 90. He had a good paying job, but got so good at detecting, he retired early and took up detecting (highly specialized objects) full time, and made more money. Fantasic guy, and he is a world class expert in his chosen field. He is doubly retired now.
Of course, he mined out the best areas decades ago.
In case you don’t already know about this wonderful television series: https://www.youtube.com/watch?v=aAud_H_0R3c