Perhaps it depends on the medication and also on your situation. I get my GP to authorize my antidepressant (Prozac) and get a 90 day supply at a time. I am sure that your doctor needs to know that you are ok in order to prescribe certain medications that are potentially harmful or subject to abuse. I often think they spend too little time though and bill the insurance company for a substantial fee for something that takes them all of a minute or two.