Usually 1 to 2, one at the start of the day and one relaxing after the evening meal. If I have enough down time, 2 to 4. I will say that smoking a pipe enhances my day and the contemplation that accompanies it makes me more inspired and creative for the tasks at hand. It's a great tool for brain storming and planning, and therefore should be encouraged at the work place. As was stated, being in the proximity of some burning leaf is nothing compared to the rest of the stuff our toxic environments subject us to. Being trapped in an office building or hospital all day can't be good for you. Everybody should just lighten up, while me and my pals light up, thank you very much!