I'd say that smoking and shooting have similar durations, honestly, it all has to do with how much is dosed at once. Say for instance you load a . into the pipe, puff it over the course of an hour or two. Thats what, 3-10 big hits depending on quality. So in a way your CNS is adjusting to it in the short term, peaks and valleys so to speak. With IV, you take that . all at once, the bolus dose is what does you in, thats why this stuff is so horrid, literally the "high" is in fact a highly-psychosomatic aftereffect of brain and body trauma. Not to say it doesnt feel good at first but, with time if you keep doing it will do your head in. When I started I could take these huge .2-.3 shots of pure, rushing my balls off etc etc and a few days after would have some sleep and the next morning be right as rain (other than hungry as ****). But staying with that cycle of 2-3 days on 2-3 days off, over a couple of years, at the beginning it starts fucking up your body but you get used to that, kinda a self-preservation mechanism kicks in (other than during the time when you say fuck it and have another bolus dose), but the psychological effects, theyre cumulative. And not only that but once it starts making you go bonkers you might not even realize it for years (some never do, the brain trauma makes it feel better and better to chase that rush as life becomes shite when youre not rushing), it's only through the realization that one is able to go back to a better life, one where youre not making everyone around you unhappy, one where youre not killing yourself slowly, that one is able to make the decision to quit. And even then its rough, went through another 2 year of 10 days clean 2-3 days use, and then another couple years of relapsing every few months("I can handle it now") - the truth is, once your CNS has gotten trained to respond in a certain manner to it, those pathways are always going to be there - the drug itself induces neuroplasticity but in the worst way. Currently the longest I've been able to make it is about 3 months, and also I've gotten off suboxone. Now usually when I use I sniff small lines or smoke a bit off foil and throw the rest away and I hate myself for it. Best of luck to you all and remember, keep using it and literal hell on Earth awaits. Might sound like some kind of D.A.R.E fluffed up public service announcement but no, it really is that bad. Best of luck to you all, Love and light.