Most new cars have a built in "oil deterioration logarithm," in which length of time is one of the factors in when the cars suggest to you via a light or "message," that it is time to change your oil. Many consider that most manufacturers are excessively conservative in those recommendations, i.e., telling you to change your oil/filter way before it is needed, partly because of the time component.I bought a 2017 Mazda-3 (grand touring) 4 months ago. I don’t drive much; there's only 2,500 miles on it. At only 4 months and 2,500 miles, the dashboard wrench light indicates it’s time for an oil change. Why would it already be time for an oil change?