title: How granular do I get with my class design when trying to follow the SOLID principles?
body: <p>I have an interface for Client Registration called IRegistrationService.  This contains one method called Register and it is implemented through the class RegistrationService.  If I wanted to have methods for Delete, Update, Retrieve for example, would I create a separate interface for each action such as IDeletionService, IUpdateService, IRetrieveService or just put all the methods into IRegistrationService.  The reason I ask this is because this is what the SOLID principles especially the SRP principle seem to ask.</p>