Regular servicing is so important to keep your vehicle running reliably. Part of an auto service is an oil change, and while this might not seem like such a big thing, the consequences of not doing it can be serious.
Without regular servicing the contaminated engine oil becomes thick and a sludge can build up in your engine. This prevents the normal flow of oil to the engine parts and can block its lubricating system and cause the engine to seize. And as you can imagine, this is not a good thing!
The oil and filter in your engine should be changed every 6-12 months depending on your vehicle's make and age. But if you tow a trailer, frequently stop and start in traffic or make lots of short trips without letting your engine warm up, it could mean that your car will require more frequent oil changes.
Make sure you follow your mechanics recommendations regarding oil and filter changes to avoid expensive repairs to your vehicle.