>In my day it took 4 years of preparation starting age 14. Nowadays kids start at 11 or earlier.
That's more due to Indian coaching companies preying on Indian's parents' extreme sense of desperation and FOMO for their children rather than any real need to start that early. I don't think any more than two years are required or recommended for preparation of the exam. The longer you stretch the preparation, the longer you have to get completely bored and burnt-out by the process.
Source: I was top 10 in JEE and personally know more than half the people who were in top 100 in my year.
That's more due to Indian coaching companies preying on Indian's parents' extreme sense of desperation and FOMO for their children rather than any real need to start that early. I don't think any more than two years are required or recommended for preparation of the exam. The longer you stretch the preparation, the longer you have to get completely bored and burnt-out by the process.
Source: I was top 10 in JEE and personally know more than half the people who were in top 100 in my year.