I just hold the hit in as long as I possibly can... to maximize absorption. It gets me higher, quicker, in my experience... so that is what I do. Some people say "your lungs absorb all they're going to absorb in the first few seconds." However, that can't be true because the longer I hold the hit in the less that comes out when I exhale. Therefore, more of it has to be staying in me. Plus I vaporize, so I know that the hit is pretty much pure THC/CBN goodness. Why would I want to exhale any of that, you know? That vapor is pure highness.

If I smoke (as in burning the weed in a bowl or jay), it is for the novelty of it or for the social atmosphere. In that case I don't hold the smoke in long at all. When I smoked cigs back in the day I could hold in smoke hits for as long as I wanted. Now that my lungs are healthy, they definitely don't appreciate it when I pull a punch of poison gas and tar into them and hold it there.