When to Use Microservices Architecture  

1. Make Sure You Have a “Really Good Reason” for Implementing Microservices

2. Iterate with Small Changes and Keep the Single-Process Monolith as Your “Default”

3. Required to Independently Deploy New Functionality with Zero Downtime

4. Required to Independently Scale a Portion of Application

5. Required to Data Partitioning with different Database Technologies

6. Technology Diversity

7. Required to Autonomous Teams with Organizational Upgrade

When Not to Use Microservices — Anti-Patterns of Microservices  , 
1. Don’t do Distributed Monolith

2. Don’t do microservices without DevOps or cloud services

3. Limited Team sizes, Small Teams

4. Brand new products or startups

5. The Shared Database anti-pattern

https://medium.com/design-microservices-architecture-with-patterns/when-to-use-and-when-not-to-use-microservices-no-silver-bullet-3ae293faf6d