Hello there

As we all listen that NCERTs are very necessary if you are about to give JEE main or advance examinations but that's not enough for any one of these examination whether its JEE main or the further level which is JEE advanced. These are not enough just because they don't include revision of complex JEE questions and with NCERT books I would suggest you to make your basics strong as these are the only things which you need to solve various Complex problems which are asked in this examination and without knowing the basics you can't do them at a faster rate which is very much important.

You can refer this link for more further information and tips that how you should prepare for JEE advanced examination:

https://engineering.careers360.com/articles/jee-advanced-preparation-tips

I hope it helps you!

Good luck!