My beloved airbrush!
When I was in my late teens, I gave up modelling for two reasons - other distractions & my dissatisfaction with my finished builds, namely the paint finish. Back then (20+ years ago), I knew that the next step was an airbrush, but being out in the sticks & without the internet as it is now, I didn't even know where to get one, let alone which one to choose or where to get the money from.
For getting back into modelling this time around, I got an airbrush before I even got a kit & I am glad I did, I can now turn out reasonably good models & almost as importantly, I have a nice shiny toy to play with.