So uptight...OK heres your answer. Its usually good until the oil starts to breakdown. Its a food substance and does have a shelf life usually 6months to a year once it has been exposed to foreign material, sunlight, heat, etc etc. believe it or not oil can spoil.lol
I know it has BA and all that but then your compound starts to break down too.. Like they said most have an expiration date. My last bottle has a 2 year window stamped on it. So try to plan where you have little to no leftovers laying around for anyone to find, ask questions or go to waste.
I will post the link if I can copy it, where I referenced this from. Its copy protected so I may just do a Screen shot.