A: First things first. You really don't have to put out a cigar. Simply leaving it in the ashtray will suffice as a cigar that sits with out the air exchange from puffing on it, will extinguish itself.

Second, a cigar can become bitter and intense towards the last fourth of a cigar. The reason is from a build up of tar and other chemicals created by burning tobacco. Depending on the cut used, and how wet your cigar gets while you are smoking, can contribute to the build up. If you tend to hold your cigar with your teeth, it tends to lend to the tip getting more moisture. Also, if your cut doesn't allow the best draw, it will leave less escape for those chemicals. The result is the build up. I, myself, tend to hold my cigar with my lips, leaving a dryer tip and allowing an easier draw to the very end.

Third, when to put down a cigar is a matter of personal preference. My philosophy is if it is a really good cigar, I stop smoking only when I can't take the heat from my burning finger tips. The reason is that some really great cigars tend to really have an intense build up of flavor that leaves you wanting more.