I asked my friend thats a mechanic. He said the 3 month rule is a scam and oil sitting in a motor is no different than the oil sitting on a shelf in a warehouse. I don't know if it's true or not, but I didn't drive my car for 2 years once and got tired of changing the oil. I just changed it before I drove it again. People buy motors from junk yards all the time and there's no way those get oil changes.