My rule is really simple: As long as there are people who are alive who care about me, then I may not kill myself. People are anchors for each other, whether they are vocal about this or not. The profound, irreversible, emotional collateral damage is not justifiable, and that's all there is to it.
Since I have family and friends who are younger than me, it's likely my rule will be in effect until die from natural causes. QED.
Since I have family and friends who are younger than me, it's likely my rule will be in effect until die from natural causes. QED.