When do I need service on my car I just bought it

You should service the engine oil about every 3500 miles. During regular maintenance the technician will inspect the vehicle and advise you of any additional concerns.

if the car is new you should read the manual due to importance of maintenance at the right time. but most of the used cars don't come with owners manual so my advice create yourself a habit to change oil and oil filter every 3,500 miles. fuel filter and air filter every 10,000 miles. transmission fluid, differential fluid and transfer case (if awd) every 75,000 miles and coolant and the rest of the fluids (brake fluid and power steering fluid) every 100,000 miles. brakes and discs should be decide by you.