I've generally tried to live with health in mind, as its something I've been relatively blessed with, so I figure, why ruin a good thing?
When I started my drug use, I was overly cautious, as I was pretty uneducated. Eventually I'd smoke out several times a week, but never noticed any negative health effects from that ... I kept my usage steady with tolerance in mind over anything.
Only with opiates did I lose my self-control, as my finances spiraled out of control along with my escalating opiate use ... but opiates are probably the least damaging of the drugs (provided you aren't injecting), so from a health standpoint, my opiate binges didn't even matter.
Only with cigarettes (which I never enjoyed), alcohol (abused thanks to its quasi-legal status) and amphetamines (nothing makes me feel worse) did I ever feel my drug use overtaking my health concerns ... crashing on amphetamines, or getting burnt out from MDxx, is the worst feeling I can possibly think of. Solitary drinking and hardcore hangovers after binges were enough to show me I really was moving past my limits ... and looking at how much $$ I had blown on opiates and all else scared me knowing I'll soon be supporting myself entirely, so I've quit all but opiates out of health concerns (which I cannot afford to buy now anyhow).
Even in my times of heaviest usage the 12-18 months, I generally tried to keep in shape through running/weight-lifting once or twice each a week, this helped me feel I was mitigating the negative effects of substance abuse ... but lately I've realized that's a pretty weak justification for continued substance abuse; its amazing how good and healthy I can feel from weeks of sobriety, combined with continued physical exercise and a quality diet
