Before the mind realizes and understands towards selflessness (There's not a permanent independent individual existence of 'I') and timelessness (There's no past or future. There's only the present moment now. Time is only the reflection of impermanent changes. Life is only now, and it's impermanent), the worldly passionate egoistic restless mind needs to adopt certain observation and restriction, as well as to be developing certain types of discipline through devoting or immersing into performing regular practice on the different disciplines, that help to weaken the idea of 'I' and egoism, that help to lessen impurities and restlessness, in order to prepare the mind for meditation and self-inquiry.
After the mind realizes and understands towards selflessness and timelessness via self-realization, the liberated egoless/selfless mind doesn't need to observe any observation or restriction, and doesn't need to be performing any kind of practice regularly to be developing any form of discipline, as the mind is devoid of ignorance, egoism, impurities and restlessness, where the mind is free from the suffering deriving from all that.
All kinds of yoga practice, is to be allowing the mind to see the truth of selflessness and impermanence, to attain direct experience or realization towards selflessness and impermanence. All kinds of benefits or side-effects are also selfless and impermanent. They are not the goal of the practice. No matter how fit, healthy, strong, and flexible the body can or cannot become through devoted regular practice, no matter how comfortable or uncomfortable one can be in any positions or movements, and no matter what is the state of the mind, all are selfless and impermanent, all will change.
It's the absence of the ego/the idea of 'I' and egoism of attachment, identification, desire of craving and aversion, comparison, judgment, and expectation, that allows the selfless mind to be resting in silence, or unconditional peace, transcending the selfless impermanent states of the mind influenced by the selfless energy fields (Gunas), and all kinds of selfless impermanent changes that constantly changing, governed by the nature's law of cause and effect.
The breath (Prana) is life. Without the breath, there is no life. The breath (Life) is selfless and impermanent. The breath cannot just coming and not going, or just going and not coming, or not coming and not going for too long. The breath is still coming and going as it is, or occasionally pausing for a few moments as it is, and eventually it will stop coming and going, as it is, regardless of whether the mind is aware of the breath, or not, and whether the mind appreciates the breath (life), or not. The practice of observing the natural breath coming and going, without trying to control or change the breath being what it is, allowing the breath to be fast, or to be slow, or to pause for a few moments, is all about allowing the mind to respect impermanence, and be able to let go in peace, devoid of any desire of craving or aversion, upon the breath stops coming and going.
Similarly, the practice of doing one's best in performing all kinds of yoga practice, actions, duties and responsibilities, but without attachment, identification, desire of craving and aversion, comparison, judgment and expectation towards the yoga practice/actions/duties/responsibilities and the fruit of the yoga practice/actions/duties/responsibilities, is about be kind to the body and mind by respecting the body and mind as it is, without forcing the body and mind beyond its limitation, without hurting the body and mind, and in the end, is all about allowing the mind to realize and understand that -
"The body and mind is imperfect and impermanent. Life is imperfect and impermanent. Regardless of whether good or bad, right or wrong, positive or negative, meaningful or meaningless, joyful or sorrowful, success or failure, happy or unhappy, literate or illiterate, knowledgeable or non-knowledgeable, kind or unkind, selfish or unselfish, healthy or unhealthy, vegetarian or non-vegetarian, long-lived or short-lived, spiritual or non-spiritual, religious or non-religious, and rich or poor, all and everyone will die. All are dying from the moment of being born, however, the mind that is free from ignorance and egoism, that realizes and understands towards selflessness and timelessness, will still be doing its best to live life as it is. Appreciating life, but without holding onto life, while making use of the selfless impermanent life existence to be performing all kinds of actions via the selfless impermanent physical body that would be beneficial to all and everyone, while not being determined or disturbed by selfless impermanent changes, of decay, weakness, illness, old age, discomfort, disability, limitation, pain, or death."
There is no fear and worry in such mind. Decay, weakness, illness, old age, discomfort, disability, limitation, pain, or death, is not something bad, or inauspicious, or negative, or sorrowful, or suffering, if the mind is free from ignorance, the idea of 'I', egoism, impurities, and restlessness, where the mind is peaceful as it is, regardless of all kinds of impermanent changes that is happening in the body and mind, and in the world that doesn't belong to anyone or anything, governed by the nature's law of cause and effect.
There is no sense of superiority or inferiority in such mind. Separateness, discrimination, and desire of craving and aversion towards the different qualities of different names and forms doesn't exist in such mind.
If there is still the sense of superiority or inferiority, righteousness or wrongfulness, goodness or badness, meaningfulness or meaninglessness, joyfulness or sorrowfulness, positiveness or negativeness, and etc, in the mind towards certain qualities of certain names and forms that it perceives in itself and others, where there is still the presence of the sense of separateness, discrimination, and desire of craving and aversion towards certain 'superior' or 'inferior' qualities of names and forms in itself and others, where there is still the sense of belonging, pride, possessiveness, offensiveness, defensiveness, dissatisfaction, disappointment, anger, hatred, greed, discontentment, fear, worry, hurt, bitterness, loneliness, guilt, regret, shame, and so on, then it indicates that the mind is still very much under the influence of ignorance, the idea of 'I', and egoism, regardless of how long and how much the mind has been devoting most of its priority/attention/effort/energy/Prana/life into practicing and/or teaching certain type of yoga, persistently and regularly, and has been achieving extensive momentary physical and mental benefits and enhancements via the devoted persistent regular yoga practice.
There's neither right nor wrong. The mind just need to keep practicing. All minds take their own pace and cause to evolve/inquire/realize, and be free.
More importantly, regardless of whether any mind is being perceived, acknowledged and identified by itself and/or others as good or bad, right or wrong, positive or negative, meaningful or meaningless, joyful or sorrowful, success or failure, happy or unhappy, literate or illiterate, knowledgeable or non-knowledgeable, kind or unkind, selfish or unselfish, healthy or unhealthy, vegetarian or non-vegetarian, long-lived or short-lived, spiritual or non-spiritual, religious or non-religious, and rich or poor, it doesn't change the truth of selflessness and impermanence. It doesn't guarantee that the mind is, or will be free from ignorance and the suffering deriving from being ignorant, but then, all minds can be free from ignorance and suffering upon attaining self-realization towards selflessness and timelessness.
The one and only GURU is the mind itself.
Inquire towards the truth of everything.