Pot smokers normally attempt to avoid breathing out the smoke as long as possible in order to enhance absorption of the active compounds. This makes sense given that pot is fairly pricey (and its supply is undependable. It always sucks when you call all your pothead friends and no one knows where you can get some.) But does it actually work? Are you breathing out a lot of important cannabinoids if you exhale right away? What about the health implications of smoking -- does retaining the smoke for longer cause more damage to your lungs? If so, is the additional damage outweighed by the need to take fewer hits to take in a given amount of THC?