A general misconception among students regarding crash courses is that even if your preparation level is zero, you can go for it and manage to score a descent rank in IIT JEE.This is however not true unless you are an Einstien ar Archimedes.Crash course is a ‘tool’ to polish your skills. Crash courses, however, don’t offer subject study right from the word scratch as they promise. Come on friends, be practical. Even the best of the coaching classes strive hard to complete the JEE syllabus within two year, how can they cover it in just few weeks.Crash course should be opted when you feel that your level of preparation is in resonance with that required for JEE.Crash courses could prove to be a boon to one’s confidence if the person has one’s basics straight. Whereas if the fundamentals are hazy, then it could deteriorate one’s confidence level a lot. Personally I feel that, in the final months of the preparation, it is better to prepare for the exam of your own, since you are the best person to judge your strengths and weaknesss. But if you are the person who has a habbit of working under some guidance then you should go for it.
In a nutshell, crash courses are an excellent tool for a quick and organised revision, or for filling the loop holes in your preparation, but don’t except them to make you a overnight success.