At my company we use Epics to categorise what I see as components of the system - various apps or islands of functionality.
IMHO Epic defines an effort that have a clear start and an end. To develop a web app is an Epic but to maintain it is a task on a given component.
I would like to propose to start using components but obviously there will be a resistance to change in the name of "we always did it this way". Are there any advantages of categorising things correctly? Is there something I can not do with epics that I could do with components? Maybe it's not worth the effort at all.