Heroin - dos and don'ts?

[Sunshine]

Hi everyone. Anyone familiar with heroin and the like? I am wondering if I purchased it now (and get a cheap heroin purity test kit) how long would it stay strong if I keep it stored somewhere dark and dry? Is heroin still working nearly as strong 3 years later for example? This isn't about drug use but for the purpose of overdosing quick and painless.

I also saw some discussion that a person would pass out before giving themselves the amount needed to die but is that true? With 0 tolerance, can't you just shove the whole syringe in 3 seconds? Otherwise perhaps a drip would work.