What is the ruling on not adhering to a single madhhab (such as the Hanafi or Shafi'i) and instead following a trusted shaykh?

A Muslim must obey Allah, His Messenger, and the scholars who act upon the Book and the Sunnah. If a new issue arises, a Muslim seeks a fatwa from whomever he believes can give him a ruling according to the Sharia of Allah and His Messenger, regardless of the school of thought they belong to. He is not obligated to adhere to a specific school of thought, for everyone's words can be taken or left, except for the Messenger, peace and blessings of Allah be upon him. A person's adherence to a specific school of thought due to his inability to know the Sharia is permissible, but not obligatory. The non-necessity of adhering to a specific school of thought is the opinion of the majority of scholars. The intention behind this must be to seek correctness and reach the truth, not to seek concessions or to trifle, otherwise it would be blameworthy.