What is the ruling on abandoning customs, traditions, and common practices and instead acting in accordance with Islamic Sharia? And are Muslims advised to do so?

One must abandon customs, traditions, and norms that contradict Islamic Sharia (definition), because Islamic Sharia is comprehensive and complete. As for customs and norms that do not contradict Sharia, Islam considers them and acts upon them. The proof of this is the jurisprudential rule: "Custom is authoritative," and His — the Almighty’s — saying: "Show forgiveness, enjoin what is good, and turn away from the ignorant," and the saying of the Prophet, peace and blessings be upon him, to Hind: "Take from his property what suffices you and your child in a reasonable manner."