It 's necessary for us including all animals to sleep certain hours.

It depends on person . However That difference doesn't make big sense.

Bt we don't have much time to live.
Less than 100 year left us to live 's not much.

If you wanna make your dream come true, you have to invest in yourself like studying hardly or training to make business.

So controling your sleep time by yourself make your way
smoothly.