Merely attending JEE coaching and going through chapter after chapter would not help you understand as to how much you have grasped and where you lack? For this you need to test your knowledge from time to time and what can be a better way to test it than giving mock tests. If you are still not convinced then the following reasons should help you understand as to why it is important:
Online mock tests such as those available at Etoosindia.com have been designed by some of the top JEE faculties from Kota. These faculties have years of experience in the field and are well-versed with the examination pattern. The mock tests designed by them are in-line with the JEE examination pattern. Resolving these give you a first-hand experience about the examination pattern which is extremely essential.
Since the IIT JEE online mock tests give you a fair idea about the examination pattern, you get to know as to how to begin your exam and how much time you can afford to spend on each question so as to complete your paper in time. Sitting for online mock tests regularly and attempting them in a stipulated time further increases your speed.
Apart from understanding the examination pattern and enhancing your time management skills, attempting these mock tests will also help you understand as to which topics you lack in. So you can devote more time on such topics or seek professional guidance on the ones you still find difficult to brush them up.
Many questions put during the JEE exam are quite tricky and you may go blank looking at them even if you are thorough with your syllabus. By giving mock tests you will be able to understand as to how to go about these twisted and tricky questions. So you will take less time to resolve these problems during your exam.