While creating your own CMS is often considered an unnecessary undertaking, you might still be interested in making one. There are some very extensive CMS’s out there like WordPress and Wix.com, and competing with these is probably a little too ambitious. But you can think smaller; maybe you want to build someone a website and give them the option to change some text whenever they please. Or maybe let them add an event to a customized agenda you made. WordPress might be too complicated for some people to use when keeping their website up to date. That’s where your own simplified CMS can come in handy.
Investigate this series further: Build your own CMS