ESPECIALLY change the oil a lot if your driving is all city. This is the biggest mistake people who don't drive often experience.
Usually, when driving on the highway the engine gets really hot, and the water with the oil evaporates.
when you dont drive as often, the engine doesnt get as hot, and that water cant evaporate. This is why you should change it often.
The oil is the most important part of an engine in my opinion. I change the oil in my cars every 3,000 miles!!! I know it's overkill but i feel better afterwards.
Its just me