Oil flows through your engine to keep it running properly. It does this by reducing friction between all the moving parts in your car. Over time, your oil will collect debris from outside and can impact how well your engine runs. If left without a change for too long, the engine will start to damage itself and may even shut down. You can tell that your oil is dirty if it is a dark color versus an amber color when the oil is fresh. You should also watch the number of months that passed and number of miles your car has travelled. The recommended time to change your oil is every 3 months or 3,000 miles, whichever is first. However, most drivers can go longer without any damage to their vehicle. It’s likely that you can change closer to 4 months or 4,000 miles. See your owner’s manual for a more accurate timeframe for your specific vehicle. Also, don’t forget to keep your oil topped off even if you aren’t due for a change.