do you count black market pills as "street drugs"?
because a lot of those are fakes with fent and god knows what else in them, especially in north america at the moment.
hell - look what happened to prince.
i daresay if that could happen to him, it could happen to any opiate user - especially in the US and canada.
if you're worried about longevity, opiates are probably not a good class of drugs to be into.
i don't mean to sound sarcastic or glib in saying that. it's just putting it bluntly.
i simply think the risks are too high for anyone buying dope or pain pills on the black market - price and supply fluctuations inevitably force a lot of users to change their DOC, sometimes onto stuff they'd prefer not to be using, just to stay well.
for example, if your only choice is between taking fent (or fent analogues) or being sick, you're probably going to go for the fent.
if the fent doesn't kill you, you'll just end up with a jacked-up tolerance, so next time you get high, you'll need more pills than normal, have to take more everytime - increasing the pressure of how difficult it is to remain a "functioning junkie".
the more it takes to keep you out of WD, the more pressure you feel to get high - and the more likely you are to end up desperate...
that's just one hypothetic situation - but tolerance tends to increase over time, for various reasons anyway. opiate addiction is just a game of diminishing returns.
the more you take, and the longer you take it, the less it does.
i don't mean to lecture you or sound patronising or condescending, but i've been through 10 years of opiate addiction and it's not something you really want to be considering a long-term part of your life if living a long life is something you aspire to.
to be fair though, i'd say the same thing about cigarettes - even more so, actually, for smokers.
you can minimise the harms of drug use, but serious addiction is dangerous, especially with illegal supply, as others have noted.
fentanyl and other chemical-weapon strength opioids that have flooded parts of the world make it extremely dangerous, and the amount of people dying reflects this.
the safest way to be an opiate addict, as toothpastedog says, is to be on some kind of maintenance program.