Headless isn't right for every project.
But it becomes necessary when:
You need multi-channel publishing
Your current CMS limits frontend flexibility
You're rebuilding your design system
You're integrating with multiple APIs
Your marketing and dev teams clash over control
A migration should not start with "What CMS should we use?"
It should start with:
Content audit
Workflow analysis
Data structure mapping
Integration planning
The CMS is a tool. Architecture is the strategy.