when to use SQL versus NoSQL for microservices

Hey everyone, I'm building some new microservices and I'm stuck on a pretty common, but always annoying, choice: SQL or NoSQL for each one's database. Some of our services are definitely relational, but others are more document-focused or work better as key-value stores. How do you decide which type of database works best for a specific microservice? Do you have any strict guidelines you stick to, or is it more about gut feeling and trying things out? I'd love to hear your methods!