Oil Change Prediction Methods

There are several tools to use in deciding at what increments to change your oil in your vehicle, and while one theory is not necessarily any better than the other at predicting the best time increments for this important step to preventative maintenance, it is important to choose a prediction method that works for you and to be consistent with that particular method.
A lot of people just stick to the old stand-by—performing the suggested maintenance every three-thousand miles or every three to four months, whichever comes first, and while this is a perfectly good schedule to follow that certainly will not harm your vehicle, unless you drive an older or higher mileage vehicle, this practice is probably somewhat of an overkill for your pocket book and is not necessary for your car. 
If you are looking for a reliable prediction method for oil maintenance, your owner’s manual is a great place to start. Most manuals lay out a maintenance schedule for vehicles, and these will include oil maintenance schedules. A manufacturer will usually note in the manual that a change between five thousand and seven thousand miles is preferable and acceptable for those who drive in normal conditions, but pay close attention to what "normal" means in this instance. Normal driving includes only those who drive at steady speeds on stretches of highway for timeframes exceeding ten to fifteen minutes each time the car is driven. Contrary to the name, that is not really a normal situation. Most of us drive in the city. We stop and go a lot. We run errands. We idle frequently, and these conditions are deemed "severe conditions," under which more intense schedules for lubricant maintenance are needed.
Newer vehicles may come equipped with a light on the dashboard to remind the driver when an oil change is needed. However, be wary of this: some vehicles have an "oil" light, but it's not to indicate that the vehicle is in need of an oil change, but that there's a significant problem related to the oil pressure. At this stage, it's imperative that you have the oil system investigated, because the light may be the car screaming at you that there's a problem. In newer vehicles, however, an oil light may be a reliable indicator for when you need to take a trip to the shop; however, be sure that the light is reset after each completed check, or its suggestions will not be accurate.
Probably the most reliable method is one that involves actually sending in a sample to a laboratory for analysis. Many fleet companies utilize these lab services to maximize not only time between changes but also their profits. Reducing the number of changes by just one each year on each car in a fleet can save the company a considerable amount of money. This is not a service that has to be performed each and every time you anticipate the car maintenance need; it only needs to be checked a few times to conclude an idea of how many miles you can drive before a necessary oil change, and because these findings almost always reveal that you can drive longer periods of time and/or more miles between changes than the standard 3000 miles, the minimal fee for the service is worth the hassle.