First of all, we would like to make it clear that the Muslim layman who does not have sufficient knowledge is not required to compare between the opinions of scholars and decide which one is more likely to be correct, but rather he should ask the scholars whose piety and knowledge he trusts. When he faces two or more opinions in a religious matter, he is to choose the opinion of the scholar whom he trusts to be knowledgeable about both, Shari`ah and life.
Let’s take reciting Al-Fatihah behind the imam as an example, In regard to this, what we see as the strongest opinion is that one must recite during the prayers in which the imam’s recital is subdued. But, during the prayers where the Imam recites aloud, one may not recite.
Elaborating on what a layman should do when he faces two or more opinions in a religious matter, the Fatwa of the European Council for Fatwa and Research states: As for a commoner, he should follow the opinion of the scholar who gives him Fatwa. Whenever he has a certain problem, he can consult an Imam or a Sheikh and follow his Fatwa. Almighty Allah says: “Ask the followers of the Remembrance if ye know not!” (An-Nahl 16: 43) And the Messenger of Allah (peace and blessings be upon him) said concerning some people: “Why don’t they inquire if they know not, verily inquiry is the cure of ignorance.” (Abu Dawood)
Additionally, the late prominent Saudi scholar SheikhIbn`Uthaymeen (may Allah have mercy upon him) said: The scholars have stated that the madhhab of the common man is the madhhab of his mufti. If their opinions differ, then he should follow the one who is most trustworthy and most knowledgeable. This is like when a person falls sick—may Allah give us all good health—and he looks for the most trustworthy and knowledgeable doctor so that he can go to him, because he is most likely to give him the right treatment than anyone else. It is more important to be on the safe side in religious matters than in worldly ones.
Furthermore, one must note that the Muslim should not choose fatwas according to his whim and desires. Also, it is not permissible for the Muslim to follow the errors and mistakes of the scholars, for that combines all kinds of evil. Hence the scholars said: whoever follows errors, becomes a hypocrite, or close enough.