Hello,i am here to help you according to your query.

As according to me It depends on person to person.

Without any doubt if NCERT done well can beat no other material but there are certain simple questions put in a complex manner that students are unable to understand. That is the reason where guides can be useful.

There is no need to go for expensive material. Try online and offline mocks and analyse your performance, your strength and weak areas etc.

Considering the whole, you will not need the other reference/coaching material.

Hope,this information helpful to you.