We should conserve fuel for the use of future generation as if they will once exhausted will can't be renewed easily as it took a long to be prepared under the high pressure and temperature of earth.
The highest consumption rate in today’s world is of fuel. They are a man’s— best friend.  fuels are created by the decomposition of dead plant and animal life that existed in the Earth millions of years ago. From the day it has been extracted and discovered, they have served the mankind and are still one of the most useful tools for human existence. The  fuels include petroleum, coal and natural gas. In fact, the whole world is dependent on  fuels to fulfill their daily energy needs. Though adoption of renewable energy sources has increased sharply in last decade, still it will take some more years to reduce our  dependance on fuels drastically.