> No you can update ONLY the micro services that are impacted by the new requirements without impacting the other micro services.
Only if the new requirements don't require a breaking API change. Microservices make API breaks more difficult, since they're loosely coupled it's harder to find all users of an old API & ensure they're updated than it is with a tightly-coupled system. Microservices make non-breaking changes easier, and help ensure all access is gated through an API.
> “we have users, so let’s do a user service. Then we have files, so let’s do a file service”.
Agreed that this is not a useful heuristic for deciding how many services you need.