Once set up, routine maintenance and updating of content can be performed by someone with little or no technical skill.
Much free support is available via online forums such as the ones on Devshed.com.
New functionality can easily be added.
A mature CMS has undergone years of testing and development by teams of developers, and therefore has relatively few undocumented bugs.
In-house personnel with previous experience in a particular CMS can be employed.
Many hosting services offer content management systems that are already installed that you can customize for your needs.
Ready-made graphics templates are available for purchase or free download for many content management systems.
Content management systems generally have adequate security against hacker attacks.
A CMS-based site can be set up in relatively little time.
Use of a CMS maintains a consistent layout and appearance on all pages of the site.
Set up can be difficult for someone without experience.
A content management system has a great deal of overhead code for the purpose of creating and operating the system framework and module system.
Customization is not necessarily that easy, particularly for someone inexperienced with that CMS. Modifications that don't fit into the framework and module system will probably be very difficult, even for an experienced programmer, due to the complex, and often poorly documented, overhead code of most content management systems.
Documentation for a CMS is often inadequate.
All the overhead code of a CMS can cause it to run relatively slowly and consume a lot of server resources.
The functionality of the site is limited to that available in the premade modules. Content management systems usually have a module to which some custom functionality can be added, but there are limits to what can be done.
Content management systems are slow to respond to changes in technology, and new versions can be infrequent.
Installation of updates to, or of new versions of, a content management system may require major changes to the existing installation, or complete reinstallation.
Although the main code of the site framework of a CMS is usually thoroughly tested and debugged, the code of optional modules that can be plugged in sometimes isn't. Some modules can be buggy and insecure.
All pages of the site have the same layout and appearance. This could be a disadvantage for your site.
