This is a question that has been asked before with no clear answer so I talked with the Seaboard/Newman oil rep. As He explained. The base oil never goes bad but over time the additives degrade. The industry standard shelf life is three years.If any retailer has any stock older they are to dispose of it. Also bulk oil in barrels degrade faster but that is hardley ever a problem as most places will go though ther stock long before then. Now this not a problem for most of us but I'm a oil horder. I've got Golden Spectro from the late 90's on hand! Is it still good? I don't know. Maybe I'll send some off and have it tested. Qwerty is that something you can do and if so how much?