It is said that wherever possible one should follow the other Math-habs as well, e.g.

Answer

There is a difference between acting in terms of the rulings of the other Math-habs and the Hadith. All the masaa-il of the Math-habs are based on the Qur'aan and Sunnah. However, the permissibility of following a ruling of another Math-hab is regulated by a principle, and that is that when acting in terms of the other Math-hab, you are not in violation of your own Math-hab. If an act in a Hadith is in conflict with the ruling of one's Math-hab, it is not permissible for a Muqallid to reject the Math-hab or to act in conflict with the Math-hab on the basis of what he has read and understood from the Hadith. While that Hadith may constitute a daleel for another Math-hab, our Math-hab will have its valid argument for not acting in terms of it. It is not permissible to become a self-appointed, cardboard 'mujtahid'.