i've never re-used a disposable needle. My mom was told when I was diagnosed 16years ago to never re-use a needle unless we have no choice, eg: there's an disasters and i've run out of needles or it's 3am and the pharmacy is closed but i need to take a shot to treat a high blood sugar.
otherwise, we've always been told to use them once and dispose, because it can lead to infection to re0use a needle, even if it's being used by the same person. unless it's a pen or one of the oooold needles where the needle part comes off and you can boil it before using it again.
i don't know if things have changed around that, but that's what i've always been told.