When will you go for microservice & when will you go for monoliths?

If your company does not have appetite for below, then do NOT go for microservices

• Rapid provisioning (Infrastructure)
• Basic monitoring
• Rapid application deployment (deployment as well as rollback)
• DevOps culture

Another very important point is, if you cannot define the service boundary right at first place, then it will be very difficult to fix later in microservices.