[Shifting to the Madhhab of Imām Zayd Regarding the Non-Obligation of Zakat in Vegetables]

Answer—and from Allah is unceasing success: The Imams of the Prophet’s Household (Ahl al-Bayt), peace be upon them, and their scholars—they are the people of truth and the ships of salvation; whoever follows their guidance is saved. What appears to me—and Allah knows best—is that it is permissible for any of their followers who are muqallids (adherents in taqlīd) to adopt the madhhab of any one of them he wishes, and to take in one time the madhhab of some of them and at another time the madhhab of another.
Imām Zayd b. ʿAlī—peace be upon him—said, as in his Collected Epistles: “Our differences are a mercy for you,” meaning that the differences of the scholars of Ahl al-Bayt in a given issue are an expansion for their followers, not a constriction—so a follower is not restricted to one of the two madhhabs that he must remain with; rather, he may take this one and, after a while, take the other.
This is what has appeared to me for the following reasons:
1 - The default is the permissibility of moving between views, and there is nothing to forbid it; whoever claims it is forbidden bears the burden of proof.
2 - It is presumed that each of the Imams has fulfilled the conditions of being qualified to be followed in taqlīd. If that is so, then each of them is fit to be followed; and in that case, what objection is there to the muqallid taking the view of one of them and then the view of another, given that they are equal in eligibility to be followed?
If it be said: They have stated that “pursuing concessions (tatabbuʿ al-rukhaṣ) is heresy.”
It is said in reply: What is meant by that is pursuing the slips of the mujtahids and their anomalous ijtihādī judgments that are repudiated. Hardly any Imam among the followed madhhabs is free of an anomalous, disapproved ijtihād—or more than one.
Source : Min Thimār al-ʿIlm wa al-Ḥikmah vol.1