Another reason not to re-use

Used for what

I thought this was talking about sewing needles. Apparently not.

straight up thought sewing needles, and how i used ones that are a couple years old

These are Tri-Beveled needles, typically used for piercings.

those are injection needles and if you need reasons like these to consider to stop re-using them, you've got fucking problems coming your way. even worse problems, if we're talking about iv drug use.
actually, nvm, everything about this post is terrifying, i'm out.

I always took this image to mean don't break the surface of the skin more than once, whether or not the injection is given being irrelevant. When I started working at my vet clinic, I was taught to always change the needle out after 3 'sticks', so that's my takeaway from this image.