The unalloyed devotees of the Supreme Lord who are totally surrendered souls do not care when they leave their bodies or by what method. They leave everything in Krsna's hands and so easily and happily return to Godhead. But those who are not unalloyed devotees and who depend instead on such methods of spiritual realization as karma-yoga, jnana-yoga, hatha-yoga, etc., must leave the body at a suitable time and thereby be assured whether or not they will return to the world of birth and death.