Any time, anywhere

"[Sri Bhagavan] once said categorically: 'For practicing atma vichara, every day is auspicious and every moment is good -- no discipline is prescribed at all. Any time, anywhere, it can be done, even without others noticing you are doing it. All other sadhanas require external objects and congenial environment, but for atma vichara nothing external to oneself is required. Turning the mind within is all that is necessary. While one is engaging in atma vichara one can with ease attend to other activities also. Besides, atma vichara being a purely internal movement, one does not distract others who are around; whereas, in sadhanas like puja, others do notice you. One-pointed perseverence alone is essential in Self-enquiry and that is done purely inwardly, all the time. Your attention on the Self within alone is essential.'

~ from the notes of an early devotee, Sri M. G. Shanmugam, translated from Tamil by V. Ganesan and included in Moments Remembered