Why model content before choosing a theme
Start with the information
List the things the organization publishes: pages, guides, products, places or projects. Define the facts each one needs and how editors will find and update them.
Give relationships meaning
A taxonomy, media attachment or navigation target should point to a stable identity. That makes a redesign less likely to break the content model.
Let presentation change
A theme can tell a new visual story with prepared data. The route owner and editorial records remain where they belong. This separation helps both editors and developers adapt the site over time.