You should pick a cigar for the amount of time you have available to smoke. If you are at a sporting event or on a golf course, choose a large cigar that will last for a long time. If you are in a cigar friendly restaurant and you want to have a nice after dinner smoke, (but don't want to stay there all night) choose one that will last about 30-40 minutes. These are just some examples. As you experiment with different sizes you will find one that you are most comfortable with.