OK,
I'll go there now.
This is a bit of a "trick" poll.
There is a right answer and two wrong answers.
When I was a teenaged hippie pothead everyone including me held the smoke in as long as possible.
We thought that made sense as you were smoking to get the effects, so logically the longer in the lungs, the more effects for the same number of hits.
But we were wrong!
People doing that now are wrong!
You only need it in your lungs for a few seconds.
Holding it in for a long time doesn't get more effects.
In the case of smoke, it does expose your lungs to toxins for longer.
Don't believe me?
As they say on the internets -- do your own research.