More and more organizations run their websites, in-house applications and other software on PHP or a variant of PHP. Therefore hiring a dedicated PHP developer may have many advantages.
Having a dedicated PHP developer or a team of developers means that they will be concentrating only on your project and will dedicate their time and resources 100% towards your organization. Whereas if you have outsourced the PHP development to another organization and share the resources with the several others, chances are that your inquiries, debugging and other modifications will have to wait their turn among other organizations who have paying for the same kind of service. There is also the security risk, if your system contains sensitive data or information. Not having a dedicated team means allowing unauthorized personnel access to this classified information. Also having a dedicated team around means that they can scope the requirements of the system directly from other employees and obtain feedback as to how the system can be improved further in order to operate more efficiently. Since the team is a dedicated to your organization it means that improvements to the system will come at no extra cost.
Having a dedicated PHP developer also means that you can make changes to your website or application faster than if you had it developed outside. Since the developers know about the code and the way the system works, they can make the changes quickly without having to go through the process of learning the system from scratch.