My dh is on day 6 of quitting smoking. The financial impact of a pack-a-day habit, combined with the bad example he feels he was setting for his voice students, and the effect on his own voice, is motivating him.
There is also the added advantage of living in the era of information, where resources are available at the click of a mouse, which has not always been true in our lifetime.
"Slavery ended in medieval Europe only because the church extended its sacraments to all slaves and then managed to impose a ban on the enslavement of Christians (and of Jews). Within the context of medieval Europe, that prohibition was effectively a rule of universal abolition. "— Rodney Stark