If you have to go on a long journey by car, you check the petrol, air, the radiator water, oil, brake fluid, water in the batteries. You go through a procedure of checking and ensuring that everything is working in proper order in your car. When you are convinced that everything is okay, then with peace of mind, you undertake a long journey with conviction and with the knowledge that you have checked everything in the car and everything is functioning all right, and there is no possibility of any accident or breakdown on the way.
Just as you check your car before a journey in the same manner, on the spiritual journey too, a check has to happen on the entire personality. What is the brake of your car on your spiritual journey? Vichara sanyam is the brake on your journey of spiritual life.
As you progress in spiritual life, you come across different experiences, understandings, realizations and perceptions which are unique to yourself. These different experiences or perceptions can alter the state of ego and buddhi, intellect, and take you towards a restricted nature or life, and not to­wards an expanded nature or life. In the Ishavasya Upanishad, it is stated that knowledge can lead you towards light, yet at the same time, it can also propel you into deeper dark ness. Knowledge can lead you towards light, yet if that knowledge is not applied in the right manner and understanding, then it may take you to even greater darkness than ignorance by inflating the ego, cultivating arrogance, close­minded ness and assertiveness which is tamasic by nature.
Therefore, vichara sanyam, control of thoughts and cultivation of posi­tive thoughts are the brakes against accidents in spiritual life.It is easy to fall prey to negative speech. In gossip and criticism, the negative, comparative, critical, analytical, judgemental aspect comes out and is directed towards another person. Speech and thought reflect what you are inside. If you have refined speech, you have a refined mentality. If you have gross speech, you have a gross mentality. Vani or vakya sanyam, control of speech, and vichara sanyam are the brakes that control the accidents of spiritual life.

The idea is to retain mental positivity, and these two mantras help.The Gayatri and Mahamritunjaya mantra should be practised by everyone regularly. As you check your car to ensure all systems are working properly, the different yogas have to be practised.
Practise your asana every morning, 10 or 15 minutes, pranayama 10 or 15 minutes.
Practise relaxation, yoga nidra either during the day or at night before going to sleep. When you practise yoga nidra at night, you don’t have to do the sankalpa ‘I will not sleep’. If sleep comes, go to sleep. Practise ten minutes of meditation, nothing too difficult or abstract.
Sit down quietly for ten minutes on your chair, bed, or floor, wherever you are. Choose a time when you are undisturbed and not bothered by anything, and are free from the mental worries and associations of work, expectation, achievement, success and failure.
In those ten minutes, sitting quietly, observe your breath. See the flow of breath in the passage between the navel and the eyebrow centre.
Say your mantra with the breath for ten minutes. This should become part of your routine in life.

Yoga Sadhana Panorama vol 8, page 20, Swami Niranjanananda Saraswati