When is it okay to start worrying?:
A friend was waiting to hear about the results of a job interview. He hadn't heard in a while and he asked me, "how long before I should start worrying?"
Of course, the answer is, "you should never start worrying."
Worrying is not a useful output. Worrying doesn't change outcomes. Worrying ruins your day. Worrying distracts you from the work at hand. You may have fooled yourself into thinking that it's useful or unavoidable, but it's not. Now you've got one more thing to worry about.