Every PHP Programmer should follow coding standards, so it is easy to read through program created by another programmer. If you are into PHP Programming, you must read and understand PHP Coding Style Guide.

http://www.php-fig.org/psr/psr-2/

Many languages have strict coding style, structure, this make code easy to read and maintain. Ruby On Rails is very popular as it forces you to code in Ruby way. PHP do not force you to code in PHP Way, so many programmers code differently, structure programs different ways, this make it difficult to maintain by another programmer or even him self afeter few years.

It is said programmers spend 40% of time re-factoring code than writing new code. That means lost productivity, with strict coding standards, this can be solved.

PHP having no strict coding standards or one go to framework for web apps, many moved to Django or Ruby On Rails.