I notice a lot of tutorials (including Sorastro's) result in good looking models that would be fine to game with even if you stopped before the highlight and finishing/weathering stages. Now whilst I'd like to go that extra mile, I also accept as a total newbie doing so may be frustrating or too much in one go.
What I'm wondering is, if you did stop at the basic level with the intention to return to a model in the future to add highlights, maybe further layering and weathering, would you avoid varnishing the model? If you did varnish, would that cause issues if you tried to return to do more with the model?