well it is said that not even teaching can replace our own self work...but more than self study , having any guidance coaching is required because of following reasons:
1.it will create good competetion with other students.
2.you will be updated of what patterns and models of questions are asked in present day jee.
3.exams will stimulate more competitve atmosphere in the institute.
4.you can easily clarify your doubts with the available faculty instead of struggling for more time.
so it is advised you to select a good institute of your choice and go with it..!
plz approve my answer..