You can implement microservice-based design on both new and existing products and services. Contrary to the belief that it is easier to develop and design a new system from scratch rather than making changes to an existing one that is already live, each approach has its own respective challenges and advantages.
For example, since there is no existing system design for a new product or service, you have freedom and flexibility to design the system without giving any thought to its impact. However, you don't have the clarity on both functional and system requirements for a new system, as these mature and take shape over time. On the other hand, for mature products and services, you have detailed knowledge and information of the functional and system requirements. Nevertheless, you have a challenge to mitigate the risk of impact that design change brings...
