How many months? I'm a lower mileage driver so I change my oil every 5 months or 3K miles whichever comes first. I use conventional oil. Oil changes cost me $24 at the dealer which includes filter and tire pressure check safety check hinge lube and fluid adjustments as required. They use 5W-20. I questioned them about synthetic and got the same response twice that basically they don't start synthetics in any car before 10K miles and with the miles I drive synthetic would be a waste of money. The 10K thing is interesting especially if it is true the TCHs come from the factory with synthetic oil in them. I can't find that documented reliably anywhere though.