Strength in individual leaf and blends is often rated in online tobacco listings and other places. It is imprecise, but certainly differences are detectable, going from nicotine that gives some a buzz and makes others sick, and some throw up, down to tobaccos so mild, they not only don't impart any sense of nicotine but impart little flavor. I have tried some stronger tobaccos, Tambolaka (sp?) and black rope among them, and more widely used stronger blends like Nightcap, C&D Bayou Night, Billy Budd and others. I've come back around to including a number of milder tobaccos in the rotation both aros and non-, and I still like Tabac-Manil Semois in thick and medium cut, which is a sturdy burley variant. What do you look for, and what do you avoid, and how do you alternate between what you consider stronger and milder blends, if you do? Tobacco and blend strength, what moves you?