Why is it a good idea to know the size of your vehicle's engine?

There are numerous reasons why it is a good idea to know the engine size of a vehicle. The size of an engine will let a driver know the horespower that the car has. It will also let the person know how much fluids are needed in the car such as oil, transmission fluid, radiator fluid, etc. The size of the engine is also needed when a person goes to buy a battery for the car. The size of the engine is also needed when you go and buy parts for the car.

I believe the answer is: So you are able to purchase the correct maintenance items/replacement parts

Items and replacement parts would be sold separately depending on the size of vehicles that they can accommodate. You should know the size of your engine to ensure that you get the appropriate size and not wasting your money on things you cannot use.