2001 Saturn SC1 Starter

I would say from what u describe that it's not ur starter if u use it everyday and it works fine it can't be ur starter if ur battery goes dead after sitting for 3 days.I have had batterys that test good but self discharge they just don't hold there charge for any lenth of time.U should have ur alternator checked there are diodes in it if they go bad it can drain ur battery also. One more thing u can check to isolate ur problem to a bad battery is to have ur car tested for a excessive parsitic draw that would drain ur batery over time. Also check and make sure ur dome light doesn't stay on map light another thing u can check is fold down one of ur back seats and look in ur trunk and make sure ur trunk light isn't staying on. Checking those things should isolate ur battery or something else just draining the battery. Let me know what u find.
Louie