Tell different ways that Visualpages can be consolidated into whatever is left of your UI?

It is exceptionally valuable and essential idea presented by the salesforce as of late. It enables to the software engineer to expand the usefulness of existing custom controller or the standard controller.

A Visualforce can have a single standard controller or Custom controller, however, numerous controller extensions.

We can state that the custom extension is the supporter of custom or the standard controller.

Example of the above case:

If there is one controller that is written and utilized by the various visualforce pages and one of them needs some additional logic. At that point, instead of writing that particular logic to the controller class (Which is utilized by numerous visualforce pages) we can make a controller extension and apply to that page as it were.