I was using 10 milligrams. .01 when I first started. Maybe even less, it is VERY strong when it's close to pure.
At the end I was 'only' using .1 to .3 a day and it was totally ruining my life, although it wasn't street dope and was much more pure. Why I am saying the end, I'm not even past acute withdrawal. I've been bedridden for like 2 weeks now! Why would you want to risk that, I'm completely useless and debilitated.
Tolerance and addiction are different. Tolerance = how much it takes you to get high, Addiction = potentially life ruining, life long struggle of cravings, tolerance increases leading to extreme financial loss, not even getting high anymore, just trying more than anything else in your life to keep that heroin going because if you run out... it's hard to imagine the Hell until you experience it. Psychological obsession with the drug so even if you manage to completely detox there are still problems.
Does anyone want to be a heroin addict? Fuck no. Absolutely fuck the fuck no, if they knew what it did. The very first step to developing a heroin addiction is trying heroin, it doesn't matter if you have chronic pain or whatever. That makes you more susceptible actually, if you already have a reason. chance are you'll like it so much you will do it again.
Another thing - it sneaks up on you, at first there will be no problem at all. You will have unlimited pain relief from perhaps 18 months before you realize that you are completely fucked. Tolerance rises so fast compared to pills it won't even work anymore, a dose 10 times higher than what used to get me high for 8 hours gets me high for 2 or 3. And if you start using again, you quickly resume the same tolerance as before and encounter the same problems. Your brain remembers. So what about when you can't afford heroin, and there isn't really a 24/7 pharmacy for quality H either. The most consistent, reliable supply of opiates is a script even if it sucks.