I call my T when, despite everything, I'm not able to pull it together. Usually it has to do with racing thoughts/ruminations or with suicidality. He's never said I can only call when it is "urgent", but I absolutely will not call him after hours or on weekends unless it is urgent. If it's not urgent, it can wait until he's in the office. Now I call him during office hours usually for urgent matters, but phone calls during work hours don't have to be urgent by any means. He really doesn't mind phone calls at all.