I never really did. I didn't inject often, especially when I ran out of veins but it'd be a combination of reusing (my own) syringes and having no swab or being somewhere public to take a shot and trying to do it ASAP, not really thinking about swabbing the site. It was mostly the former though. I might light the actual needle with a lighter or something but I'd be too focused on trying to find a vein that I wouldn't give a shit about swabbing the site. I did quite often wash the site in a sink with antibacterial soap.
I never got an infection at a site that I know of and caused way more damage by missing veins and also using lemon juice to shoot. Had small blood clots as well which go away after a while. My habit had always been on and off as well so I'd have sporadic lapses into using and would start with smoking, try shooting because I wanted a better buzz and then I'd stop, going back onto an ORT. Reusing the same syringes too was damaging as the ones I always got are meant for single use and having them wrapped up in the packet they came in in a coat pocket surely didn't help, nor the fact that they eventually become blunt etc.
I've never shared and have had plenty of blood tests since I stopped. I'd be interested in knowing the efficacy of swabbing before injecting given that I've never had an infection or anything as a result of not swabbing. Actual use would mostly be a now and then thing anyway but could sometimes lead to a habit, though not always. In an active habit (I'd say two weeks and more of daily use), I'd be more likely to smoke due to the simple fact of not wanting to waste to waste gear - missing a shot when you're sick or getting sick is incredibly frustrating to say the least, especially if you've been waiting 2 hours for your shit.
Now that I think back, I would normally use those swabs after a shot. Dunno why. Seemed cleaner to me but I am weird about hygiene (over the top hygienic about most things but this goes out of the window by and large when you have a habit as anyone who has had one will likely tell you).
