You can imagine the CMS as a tool to take care of what is stable in your site / blog

• your articles
• your pages
• your media: pictures, videos, pieces of music
• the links between the components, even if you rename them
• etc

Before CMS existed, if you wanted to change the design to have it more on-the-fashion, you had to retype the whole content. Exactly like me from my old blog to the new one :((

Once you have your content in WordPress for instance, you can change the theme without loosing your content. It is for the biggest part immediately operational in the new layout. 

If you remember my schema on my conclusion page, the part of your architecture which is the most stable is the WP itself. Consider it as your foundation. Some customization of the themes can be lost when you switch from one theme to another. But the recurring custo's (menu, categories of post) are preserved. What magic isn't it? You can play around before choosing your theme without risk of loosing your content

Plugins customization are, as far of my experience showed it, lost when you switch from one competitor to another one

CMS are also precious if you need to have a website in several languages. In my country (Belgium) we typically need EN, FR and NL. But I chose the lazy option: only English 😉

That was all I wanted to share with you about my blog experience. Feel free to comment on this page or to send me feedback and sign up for my news letter on my contact page