Often, perseverance isn’t a virtue at all but an incapacity to reevaluate your conclusions when new evidence comes in.
Example. I spent 10 days trying to hire a person to teach two courses that are important to our program but that this Fall have no instructor because of a combination of retirements, sabbaticals, and course releases.
I did everything I could think of but it wasn’t happening. Then I went for a swim and after half a mile suddenly realized that I shouldn’t be hiring anybody to teach these courses at all. It wasn’t working out because it wasn’t supposed to.
By the end of the mile, I knew exactly how to reshuffle things so that the important courses were taught by an experienced colleague. And from there, it was easy to hire people to teach what was left.
If you’ve been trying for a long time and it simply isn’t happening, there is a possibility that it’s time to walk away and do something else.