If you plan on keeping the car until it dies you should switch to a good quality synthetic oil(Mobil 1) and a quality oil filter (Wix is usaully what i get, FRAM is junk, the rest arent bad, Mobil one is the best but a bit overpriced) If you plan on keeping the car for less than 200k miles just keep doing what your doing. One thing though. People that put synthetic oil in there cars tend to notice better gas mileage and this two thick argument makes no sense. 5W-30 dino oil is the same thickness as 5W-30 synthetic. Just buy the one that matches your car.