Hello,

I have done my root canal in the month of August 2013. But I have not put the crown due to many reason and I am not using that root canal ed tooth.. It's that very important to wear a crown?

Please let me know..

Eventually the tooth will crack off pieces, because the tooth is dead after the nerves have been killed. It's best to have the crown in place before a piece breaks off. It costs more if you wait for that. You can get what is called a temporary crown for less cost, which might last years if you don't chew on it.
Even a crown can have future problems. I learned that the hard way - an infection got into a vertical crack under the crown, and went into my jaw and whole body, and I had severe bronchitis for 10 months. It didn't go away even with the newest antibiotics, but did go away 2 days after the tooth was removed.