I always try to design in a way, that using abstractions/shared logic is optional.

I've worked in too many projects, where every new feature needs to be built on top of existing abstractions, that often lead to severe restrictions if something slightly different is required. I always try to create reusable units/components, that can either be used as intended or replaced by something that behaves slightly different if needed.

Components are not necessarily frontend components, this extends also to backend logic.