Once and done, then I bury them in the sand at the local park with some used toilet paper...lol...JK...
lol.... Seriously, the once and done part it true. But I use a sterile 18 to load my darts for the week, then put a sterile 23 or 25 at each end depending on the sites I'll be hitting that week.
I don't inject anymore but a few years back when I ran winny, GH and Primo, I used to take a new syringe and a new needle each time. It's much safer if you ask me.
I never use the same needle for more than one injection but i use the same pin to draw from ampules. I usually draw with a 21g and inject with anything from 22g to 27g.
NOpe. I use a pin to pull and a new one to push. Their so cheap ,why not?! Ever see am up close picture of a needle that was put threw a stopper just once? You wont use it the second time, trust me.
Why would anyone? If you have $10-$15 to squirt in to your glute each time how hard is finding another $0.50 in the couch cushions to get an extra pin?