How should I inherit IDisposable?

Question

Class names have been changed to protect the innocent.

If I have an interface named ISomeInterface. I also have classes that inherit the interface, FirstClass

Answer 1

If you know some implementations of ISomeInterface require disposal, then the interface should inherit IDisposable, even if concrete implementations of the interface don't have anything to dispose of.

For instance, in the BCL, IDataReader implements IDisposable, even though one could certainly imagine data reader implementations that don't have external resources that need to be disposed of.