I only stopped buying pipes for 6-12 mos. I just loved pipes. loved thinking about them, and especially loved looking at them and buying them. I didn't waste time examining a pipe without a price tag as considering whether I could afford it was integral to its evaluation.
But when I started I regarded pipes simply as tools to smoke and felt that tobacco was the point. So I bought quite a lot of it. But then I noticed that a lot of the older guys really loved pipes, and since they were older, they obviously must know better, must know more.
So I began studying pipes online, going from site to site to find what I liked and why I liked it, a lot of comparison and contrast.
I tried to understand all the ideas others had about pipes, and believe it or not it took 18 years to get an answer to a term that I came to think was a ghost in the wind, engineering. Only last week did I get an answer from Chris and Todd Bannard.
My ideas of the factors affecting the smoke are limited to:
1. impeccable drilling, especially at the chamber draft, that has been engineered to promote airflow; also within the stem.
2. comfortable stem. I was looking at some Italian pipes with stems that conformed to the shape rather than the shape adjusted to include a comfortable stem. I found the chunky, clunky bits horrid. To smoke then you would have to smoke the pipe exclusively hand-held.
3. stem flush with shank, although even if accomplished at POS, the fit of the mortise can change.