Project workflow questions (Link and Append)?

Hi All.
I am really enjoying working on my first project as a way of learning Blender but I’ve got to a point where I can see my own inexperience is going to cause me lots more work than I really need to do. This 3D stuff is not going to be my job, I’m a lecturer in Electrical Installation but a hobby and a tool to create narrated videos for my students most definately.

My question relates to the workflow and project as a whole.

As you will see from the attachments below I have two simple models that are currently in two seperate .blend files. I 've done a fair bit of work on the first one today with the oscillator screen and sine wave. as you can see the models are very similar with the only differences being the arrangement around the carbon brushes and the oscillator screen. For consistency of the eventual videos I’d like a scene setup where I can have all the lights and materials set up and just bring in different models to animate etc.
My question then (at last :rolleyes:) is, should I be keeping everything in one .blend file with seperate layers for the lighting rig and models etc or should I be using link/append etc?

Thanks for any help anyone can give.