Probably the biggest question you face as a developer every single day is “where to put your code”? Should you use repositories or query classes? Should you have one class or two to represent your domain object? Should you write a new class or extend an existing one?
In short what constitutes a single responsibility and how separate should your concerns actually be?
MediatR Notifications can help with some of these thorny issues.
jonhilton.net/2016/08/31/how-to-easily-extend-your-app-using-mediatr-notifications/