I try to build a library of cabinet doors, and when I need one I insert it in my project as a linked component, then break the link so I am able to edit the variables (and make a door fit for a specific cabinet).
The problem with this approach is that improvements to a door model don't get copied to my cabinets. This means I have to delete all doors in all cabinets when I make an improvement to the design. Which is fairly stupid...
This could be solved by adding an option to 'make editable', like we have the 'break link' option, and woud make Fusion 360 much more useable for people who want to reuse existing data, but want to keep updating this data as well...