iOS最佳实践：一个场景一个控制器或多个场景一个控制器？

I am new to iOS development and has started working with Swift. I am currently using a Tab Bar Navigation which contains 3 tab/navigation. Should I subclass the UIViewController and use it for all 3 scenes or each scene should have its own subclass of UIViewController. What is the best practice on this?I am new to iOS development and has started wor