Who requires a guru? It is not a fashion, that one has to accept anyone as guru. No. A person requires a guru when he is inquisitive, tasmād guruṁ prapadyeta jijñāsuḥ, when he is very much eager to understand the spiritual, śreya uttamam. Uttamam. Ut means transcendental, and tama means darkness. This world is called darkness, ignorance. So one who wants to transcend this position of ignorance and wants to know the transcendental subject, means spiritual subject, brahma-jijñāsā, he requires a guru, not any person, other person.
-Lecture Chaitanya Charitamrit Madhya Chapter 20 Verse 101-104 - Bombay

vande gurūn īśa-bhaktān
īśam īśāvatārakān
tat-prakāśāṁś ca tac-chaktīḥ
kṛṣṇa-caitanya-saṁjñakam
I offer my respectful obeisances unto the spiritual masters, the devotees of the Lord, the Lord’s incarnations, His plenary portions, His energies and the primeval Lord Himself, Śrī Kṛṣṇa Caitanya.
-CC Adi Lila 1.1