What is the purpose and advantages of different lengths of contract in futures

If we buy a future stock or index in India we get three different length contract options, currently its 30 july, 27 aug and 24 sep. can any one tell what is the purpose of using 3 different length contracts instead of one? Is there any advantage or dis advantages of using short and long term contracts? if yes what are they?

Should I need to ask my doubts about futures in the already opened question?

btw what is the purpose of futures if we already have stocks ??

if you answer that you will get answer to your question.


Futures purpose is to hedge.

Hedge for how long? the length is your expiry date distance.

Some choose to hedge for shorterm a month, some for 3 months... there are long term futures with expiry running into years (but such long term futures/options are not available in NSE from my retail trader limited knowledge, google: LEAP options).