There are a number of states one may have in following the legal position of an Imam other than one’s own, among them:
(1) to believe that the other Imam’s position on the particular question is stronger, in which case it is permissible to follow him in deference to what one believes to be the sounder position;
(2) to believe that the position of one’s own Imam is stronger, or not to know which Imam has the stronger position on the question, in both of which cases it is permissible to follow the position of the other Imam whether or not one thereby intends to take the way that is religiously more precautionary, in which case it is not offensive, though if it is a mere stratagem that is not intended as such (i.e. not intended as being religiously more precautionary) it is offensive;
(3) to intend by following the other Imam to take a dispensation when there is a need for it (such as a Shafi’i circumambulating the Kaaba at a crowded hajj who follows the position of Abu Hanifa that touching a woman does not nullify one’s ablution), in which case it is permissible to follow the other Imam, unless one believes both that the position of one’s own Imam is stronger, and that it is obligatory to follow the more knowledgeable of the two;
(4) to intend merely following the easier way of taking a dispensation when (neither (2) nor (3) above is the case, and) one does not believe that it is the stronger position, in which case following it is not permissible, as Subki says, “because one is then merely pursuing one’s own caprice, and it is not for the sake of religion”;
(5) to do this frequently, so as to become one of those who seek out dispensations, taking the easiest ruling from every school, which is also forbidden, as it connotes a dissolution of the limits of legal responsibility;
(6) to assemble by such a procedure a single composite act that is unacceptable by the consensus of scholars, which is impermissible, such as when a Shafi’i follows Imam Malik in considering dogs to be physically pure, but only wipes part of his head when performing ablution (wudu’), for in such a case his prayer is not considered valid by Malik, because he has not wiped his whole head, nor yet by Shafi’i, because of the physical impurity of dogs (though it is unobjectionable to piece together such a composite act by way of following the scholarly evidences supporting each part, if one is qualified to appreciate them, since then one has become a mujtahid on the question);
(7) or to follow one’s original Imam in doing an act whose consequences are still in effect when one subsequently intends to follow another Imam, despite the continued existence of the first act’s consequences; such as a Hanafi who, by right of being a neighbor, acquires a piece of land by preempting a neighbor’s sale of it to another (since one of the purposes that permit preemption in the Hanafi school is to prevent property adjacent to one’s own from being acquired by an objectionable neighbor (though the Shafi’i school does not allow preemption for such a reason))—but when a second neighbor for the same reason preempts the Hanafi’s taking possession of the land, the Hanafi refuses to allow the second preemption on the pretext that he now follows the Shafi’i school on the question, which is not permissible because it confirms that he is mistaken, either by following the first opinion or by following the second, while he is but a single responsible individual.