There is one thing Quaker State used to do (and may still be doing-I have not looked closely at a Quaker State oil bottle in quite a while) was put the year of manufacture for the oil on the bottle. I wish everybody would do this-I wish it would be required. How long has that oil bottle be on the shelf in the auto parts store? If oil classifications have not changed for a while (SL, SJ, etc.), how do you tell? Of course, if there is dust on the oil bottle, then it has been there a while. But if SL oils have been around for a while, that oil bottle may have been on the shelf for two years, or longer. I remember seeing an ad for Quaker State oil being on sale, and when I went to the store and checked the bottles, it was obvious that those bottles had been on the shelf for perhaps four years! This is something that causes me to hesitate in buying an oil that may be very good but does not sell as well as some others-the bottles of that brand of oil may have been sitting on the shelf for a long time. The one good thing about Quaker State, you could look at the bottle and see if the oil at least came out sometime that year. I have seen a lot of synthetic oil bottles that obviously have been on the shelf for a long time. Synthetic oil is more expensive then conventional oil and does not sell as rapidly. If you happen to use four year old synthetic oil (without realizing it has been sitting on a store shelf that long), is it still better then fresh conventional motor oil? The brands of popular motor oils probably sell faster-the bottle of Pennzoil and Quaker State, for example, probably don't normally stay on store shelves very long.