The first stage of life is called Brahmcharyāshram. One of the meanings of Brahmacharya is to search for the ultimate ‘Truth’. It is up to the age of 25 years. The main goal of this stage is to gain knowledge and practice self-discipline ( Dama). All pleasures derived from our senses (taste, touch, smell, hearing, & seeing) are given up so that the student can concentrate on his/her studies. This - giving up of the pleasures of senses - is called Pratyāhār
( याहार) in Sanskrut.
All
the
practices
recommended
under
Brahmacharyāshram are performed in Vānprasthāshram and Sanyāshram too.
यदा संहरते च अयं कूम अ ङा न इव सवशः ।
इि या ण इि याथ यः त य
ा त ठता। ॥२ : ५८॥
Just as a tortoise (in face of danger) withdraws all his limbs
(under his shell),
A wise person withdraws all his senses from the objects
that gives (temporary) pleasure.
Bhagavad Gitā, 2:58
Another example is that of a moth being attracted by a flame (pleasures of the sense organs), starts to circle around it (thinks about it constantly), gets closer and closer to the flame (wants more and more of that pleasure) and ultimately burns itself alive (something like a drug overdose).
जहा त यदा कामान् सव न् पाथ मनोगतान् ।
आ िन एव आ ना तु ः थत
ः तदा उ ते ॥
To become (a person focussed on a noble goal)
abandon all (selfish) desires (for pleasure)