If you change the oil in your vehicle’s engine on a regular basis it should last the lifetime of your vehicle or at the very least you will avoid premature engine wear due to improper lubrication. That is the issue however, you need to stick to scheduled maintenance intervals. The old tactic of inspecting the color of the oil on the dipstick as a means of determining its condition hasn’t been valid for many years. Reason being is that modern oils have detergents already infused within them that pull gunk and particles off of the engine's moving parts and suspends them within itself. This is why oil quickly becomes blackened.
However there is a limit at which the oil becomes saturated and both the oil filter and the oil itself cannot contain the harmful particles. Along with oil reaching saturation it also ages with time and this adds to the decrease in protection. Regular non-synthetic oils deteriorate quicker and thus needs to be changed more frequently, while full-synthetic oils have less impurities and higher/lower tolerances which allow them to extend your oil change interval. It is widely advertised that you no-longer need to change your standard oil every 5,000km. The new widely distributed figure for oil changes is anywhere from 7,000-12,000km for standard oil. This change can be attributed to improved engine designs, higher fuel grades, and advancements in motor oils. Time is another variable that should not go unnoticed. As the particle waste mounts within the engine, comes loose and get absorbed by the oil they are now open to oxidation and other denaturnments. While these particles degenerate they pollute the oil without the engine ever needing to turn or kms being added which is why time constraints are just as important as km constraints.
A factor not often taken into account is the reality that in Ottawa and most of Ontario and Quebec, severe conditions are present. Severe driving conditions as it pertains to motor oil are: extensive idling or driving frequently in stop-and-go traffic; operating in cold temperatures below -12 degrees celsius or extreme temperatures above +32 degrees celsius; extreme humidity; repeated short-distance trips of less than 8 km; towing a trailer or hauling heavy materials. If you do drive in any one of these conditions in a typical week, you are driving in severe conditions, and may need to change the oil more often. We recommend every 5,000km or 3 months for standard oils and 7,500km or 5 months for full synthetic oils. As much as oil change frequencies are important you should still be checking your engine oil level every 2 weeks to ensure its not low (from leaking or burning off).