For the most part, modern airbrushes were designed for easy to disassemble for cleaning. The nozzle and needle will eventually wear out and need replacement after repeated cleaning. This includes the Badger 100 and 200 series. The exception is the Aztec AB. Aztec discourages user from taking their AB apart.
However, you do not exchange nozzle and needle for different paints. You will be better off buying a second AB.
I don't have a Badger AB. I use Paasche and Iwata because they are cheaper and easier to get parts locally in my situation.
For modeling, I use the Iwata HP-CS with medium 0.3 mm needle mostly. I have another fine 0.2 mm needle AB which can paint very fine line with very thin paint. But I don't use it much.