Missing services can cause irreparable damage to your car.
When fuel burns inside your engine, it leaves little carbon deposits behind. Engine oil is designed to wash these deposits off the cylinder wall and carry it to the sump. When too much of these deposits are in the oil, it acts like sandpaper in your engine, grinding away at critical engine components. (See picture for a shiny new crankshaft).

Once these components are worn, A OIL CHANGE WILL NOT RESTORE THEM. They are worn forever, and cannot be fixed without a total engine rebuild.

Rule of Thumb about servicing:
1. Services should be 6 monthly or 10,000klms – whatever comes first.
2. Don’t go over 10,000 kmls (11,000 is ok).
3. If you not doing 10,000 klms, NEVER let it go for more than 12 months – 9 months is preferable
4. If you don’t like spending money on your car and regularly stretch your services, you should use more expensive oil. Cheap oil and long service intervals are asking for trouble.