Say a dr writes two prescriptions one month and only assumes they wrote one. And say you held onto that script because, well lets face it, doctors are expensive and it's a nice safety net to hold onto. My question is, since he wrote both of them, is it illegal to get the second one filled at my usual pharmacy that I get anything else filled at. Meaning it won't overlap too early or something like that. And it is within the 6 months that a script like that is good for. Let me say that the reason I would even think about this is that its expensive to go to some doctors. The doctor should have not been such a space cadet really. Lets say that this doctor forgets and writes other peoples names on other scripts and people have had to go back and get it fixed

How do you know the doctor only thinks, they wrote one. If you know the doctor only intended to write one, but did two in error, then if you use it, you are doing a fraud, since you know and are aware that there is only suppose to be one.

Also as a note, normally they verify the prescription with the doctors office and /or notify them of it, when they fill it. So your doctor and/or office should be aware of this.

How serious the doctor's office will take it, will depend often on what the medication is for. A high blood pressure pill ? Or a narcotic

It would be such a simple thing to verify if it was a mistake, or done on purpose to keep you in meds. Why would you even consider taking an opportunity to technically steal a prescription? The right thing to do is ask and find out to either correct the situation, or clarify it.