Until when should you persevere?

There are multiple quotes around perseverance (and images similar to the one in the post), and I’m all for it because I tend to believe most people give up too soon. However, until when should you be pivoting (fancy word for failing)? Until your run rate goes dry, until Nth pivot, until x event? What are the N and/or x?

This is why I write these ‘daily thoughts’ posts.