Once a year or every 50 hours of use.
After every flight a plane changes its oil
Only hybrids need oil changes. Electric cars don't need any oil changes because they don't use oil. The internal combustion engine is replaced by a electronic motor.
when the oil on the dipstick changes color from a clearish golden brown to brown or black then you need to change your oi.
no
At least twice a year.
It would depend more on how many miles you go before it needs a quart of oil. A healthy engine should go between oil changes without adding oil.
Yes, dealerships do oil changes. However, they often take longer than fast oil change places, and they are frequently more expensive as well.
Your engine is either leaking oil, which is easy to detect, or it is burning oil due to worn parts.
Change the oil filter every time you change the oil.
whenever you change the oil
Level should remain fairly constant. oil changes 3-5k mi. If you are losing oil, that is a sign of wear.
Change the oil/filter every 5,000 miles if you use conventional oil, and every 8,000 miles if you use synthetic.