Aparigraha means to have only that which is needed for the protection, development and nurturing of the body, mind and intellect.
To keep with oneself what is not necessary actually depletes the society and nature. When one practices for the realisation of Oneness, it is important that his or her behaviour should be aligned with the sustainability of Samashti and Srishti. Thus practice of Aparigraha means non-gathering of things not absolutely essential for a person. It is not just things but persons even get cluttered with the past happenings, opinions, etc which is again a great hindrance in quietening of the mind.
Moreover, one gathers more things thinking happiness lies in it. But seeking happiness in materials is detrimental to the practice of Yoga. Mind also gets cluttered with many thoughts of acquisition and keeping these things with oneself which is not congenial for the practice of Yoga.
The one who is established in Aparigraha gets the knowledge about past and future births, one also gets the knowledge of how to live life.
Yamas discipline us to the roots. And therefore these are very important. Its importance is :
These laws are universal and therefore, are to be followed by taking time, place, purpose into account so that oneness is protected.
Other Angas cannot be practiced all the time for example Asana or Pranayama or Samadhi but Yama needs to be practiced always and by all.
These five Yama should be practiced by all, every woman, man, child irrespective of time, place, age, community, nation, and position.