Believe me solving previous year questions is the most important part of JEE preparation. These questions must be solved to get a good rank in JEE and hey! Who told you that IIT does not repeat questions? Let's look at this point from both mains and advanced point of view -
- JEE Mains- Some previous year JEE advanced questions repeats as it in mains. Apart from this in the chemistry section you will find some reactions repeating after every 4–5 years( of course question would not exactly be same). In maths and physics also questions do repeat. So previous year questions must be solved for JEE mains.
- JEE advanced- Question do not exactly repeat but from past 2–3 years some questions are repeating in maths. In chemistry also you will find some previous year questions in options of more than one correct type questions.
But the reason why I was calling them extremely important is that JEE advanced syllabus is very big but the team that sets JEE question paper focuses on some important topics only and you can identify these topics only by solving previous year questions.
Also you will get ultimate confidence if you will be able to solve previous year questions and confidence is more important than knowledge for clearing JEE.