airbrush needles

Yes.  Needle diameter, length, and taper are typically brand specific.  Replacement needles are sold usually with a replacement tip.  It is possible to convert from one size to another as that is standard within a manufacture's line.   
Ive gotten on Badgers sale email list and wait for their 2-fer sale and pick up new needles & tips for a brush refresh

That's good advice. I do that too. I've learned that protecting the needle tip is really important so I keep a big binder clip clamped over the business end of the a/b when not using it.

Bill

As confirmed above. Needles are uniquie to the airbrush.

There might be some cases where the same needle works in a couple different airbrushes, but that needle will still be specific to the brand or model line.

Another thing to consider is the needle and seat are very high precision. They have to be shaped just right and the needle has to match the seat. So I would stick to the brand name parts.