One should learn how to associate with the devotees of the Lord by gathering with them to chant the glories of the Lord. This process is most purifying. As devotees thus develop their loving friendship, they feel mutual happiness and satisfaction and by thus encouraging one another they are able to give up material sense grantification, which is the cause of all suffering. — Srimad Bhagavatam, 11.03.30.
To chant God's holy name means to associate directly with Him.
Good association means association with one who simply accepts the Krishna as his worshipable deity.
If the devotee feels that, "I can be Krishna Conscious without the association of devotees." it is very dangerous situation. More we separate from devotees, more we bounded by the attacks of Maya. The material world is designed to struggle to exist. So, Srila Prabhupada made the situation minimum by having Krishna conscious temples, communities and farm projects, so devotees can live in association with devotees.
Association is very important. It acts just like a crystal stone, which will reflect anything which is put before it.
Nectar of Devotion, Chapter 12,
Srila Prabhupada