Drawing and injecting with the same dulls the pin. It can be a little uncomfortable, especially if you are dispersing over numerous sites. I don't really dig 3 mls all in one place.
18 to draw. Switch tips. 22-25 to inject and throw away.
Too many guys I know reuse. Not safe in my estimation. I know dudes who been reusing for years with no probs, but I don't consider it proper sanitary hygeine.
Whatevah...