What are the circumstances under which a weaker opinion may be acted upon?

The permissibility of adopting dispensations (rukhsa) stems from two main reasons: 1. Alleviation in situations of need to avert ضرورة (dire necessity) or to accommodate a recognized hardship. 2. Prioritizing a higher benefit or averting a greater harm.

Shaykh al-Islam Ibn Taymiyyah clarified that the benefit of unifying hearts in religion is greater than the benefit of performing recommended acts (mustahabbat). He substantiated this by citing the Prophet’s decision not to alter the structure of the Kaaba and Ibn Mas'ud's prayer behind Uthman, completing the prayer rather than shortening it.

The Islamic Fiqh Academy has affirmed the adoption of Shar'i (legal) and Fiqhi (jurisprudential) dispensations, subject to certain conditions, including: The opinions adopted must be considered valid according to Islamic law. There must be a need for adopting them. The person adopting them must be capable of making a choice. It must not lead to impermissible "talfiq" (piecing together different juristic opinions in a forbidden manner) or result in an illegitimate purpose. The person seeking the dispensation must feel at ease with it.

Talfiq is prohibited if it leads to adopting dispensations out of whim, or if it violates the stated conditions, or if it overturns a judicial ruling, or if it contravenes scholarly consensus (ijma'), or if it results in a composite situation not approved by any of the mujtahids (qualified jurists).