Dear Nikita, this answer totally depends on the choice of your chapter which you are preparing for JEE Mains. Some chapters are very important and have the maximum marks weightage, there are also some, which are averagely important, you can except 1-2 questions from them and then there are chapters which appear in the question paper after every 2-3 years. So, if you have less time, you need to make a good choice of the chapters which you are going to prepare for your mains.

I hope this helps you!