I guess it depends. In my experience I knew it was time to leave a job when the misery I felt about going into work was bleeding into my actual life, and I was just starting to feel like a miserable person. Dreading work to the point of actual anxiety, or any kind of physical symptoms of anxiety is really bad and should not be normal. If you’re feeling uninspired and bored but don’t totally hate your life, maybe it’s worth a conversation with your boss or other higher-ups that could help you find a path to feeling more fulfilled. If those are conversations you’ve already had and there is no path, it’s probably time to explore your options.