How do you decide what to cover with integration testing in your projects?

[Alok00k]

I have been trying to understand how different developers approach integration testing, especially when working with applications that have multiple layers such as APIs, services, and databases. On paper the idea is clear, but in real projects it becomes less obvious where integration testing adds the most value.

Do you focus mainly on critical paths or do you test a wide range of interactions between components. How do you decide when an interaction is important enough to test as a group rather than as isolated units. I often find myself unsure whether I am testing too much or not enough, and I am interested in hearing how others find the right balance.

If you have patterns, habits, or simple rules that guide your decisions, I would appreciate learning from your experience. Understanding how different teams structure their integration tests would help me refine my own approach.