Extending or including - what is better in Twig?

Question

Why Twig documentation recommends to use extending rather than including? Symfony 2 documentation says because \"In Symfony2, we like to think about this problem differently: a

Answer 1

Twig extension is different and far more powerful than include. Try thinking about extension as coming at it from the opposite of the way you are thinking about include. With extension you can start with the end view (i.e. about.htm) and working backwards, adding the layers that you need to make the page on the site. At each level, with extension the blocks of content either overwrite or add to the parent content for that block.

"Include" isn't as flexible, you are starting with the base template and work your way out to the about.htm view, and you can't work with common blocks of content across the different files.

Check out this bit on three-level inheritance, which is a common extension pattern: http://symfony.com/doc/current/book/templating.html#three-level-inheritance