Hazardous waste is waste that poses substantial or potential threats to public health or the environment. In the United States, the treatment, storage, and disposal of hazardous waste is regulated under the Resource Conservation and Recovery Act (RCRA).
Porsche recommends that the oil in the Boxster be changed every 15,000 miles as a part of the normal maintenance procedure. The recommended oil is Mobil 1 comes in several different grades. If you wish to change your oil more often and want to avoid some of the expense associated doing so, you can change it yourself.
The instant oil change places say you need to change 3 months or 3,000 miles, and that's not a bad idea, but you can stretch it. The State of Michigan does oil changes on its fleet cars every 5,000 miles. Many manufacturers say to change the oil every 7,500 miles.