Niti:
I just completed my PMP certification this month and I agree that you should listen/read all the videos/references/material to gain more broad insight and perspective. After missing some questions in practice exams, I paid more attention to all the additional videos, glossaries, external references and any other term or principle that I had not necessarily paid attention to outside of the process groups and knowledge areas. Moderators and other contributors always gave me excellent advice.
All in all, I believe that the more comprehensive the approach, the more comprehensive the understanding and likelihood of success.
Good luck with your studies.