Question: How long did it take you to climb the spiritual ladder?Sri Chinmoy: In this incarnation it took me twenty years to climb the spiritual ladder, even after I had climbed to the top in previous incarnations. I know about my past incarnations. Even in my previous incarnations I attained God-realisation. It is up to others to believe this or not. After attaining the height of nirvikalpa samadhi in this incarnation, I had to practise meditation most vigorously for twenty years, from the age of twelve to thirty-two. This subject is most difficult, and one has to practise daily for eight, ten, twelve hours or more if one really wants to reach the Highest. This eight hours also has to be done most sincerely and most devotedly. It is a very arduous task.
Sri Chinmoy, The inner journey, Agni Press, 1977