Microservices Architecture vs Monolithic Architecture

Difficulties with monolithic application, when it grow 

• Large monolithic code base makes complicated to understand, especially for new developer
• Scaling become challenging
• Continuously integration / deployment become complex and time consuming. You may require dedicated team for build and deploy
• Overloaded IDE, Large code base makes IDE slow, build time increase.
• Extremely difficult to change technology or language or framework because everything is tightly coupled and depend up on each other.

Privilege with Microservice architecture, when it grow 

• Each microservice is small and focused on a specific feature / business requirement.
• Microservice can be developed independently by small team of developers (normally 2 to 5 developers).
• Microservice is loosely coupled, means services are independent, in terms of development and deployment both.
• Microservice can be developed using different programming language (Personally I don't suggest to do it).
• Microservice allows easy and flexible way to integrate automatic deployment with Continuous Integration tools (for e.g: Jenkins, Hudson, bamboo etc..). The productivity of a new team member will be quick enough.
• Microservice allows you to take advantage of emerging and latest technologies (framework, programming language, programming practice, etc.).
• Microservice is easy to scale based on demand. In a nutshell, monolithic vs microservice architecture is like elephant vs ant approach. What you wants to build a giant system like elephant or army of ant, small, fast and effective.