Yeah thats why I refered to irons per loft. I mean calling a club a 4 iron doesnt mean much when it used to mean a 3 iron or 2 iron. And even then they are off by a degree or two. But on average people hit 30 loft irons about the same as 20 years ago.
I was in a golf shop the other day and noticed on the Hogans they don't even name them numbers. They use the loft number.
Its also a classic method of regulating distance while using a very consistent chipping motion. Developing the skill to regulate distance by varying the length of swing takes a lot of practice, using a variety of clubs makes it a whole lot easier to learn. In the long run, both methods of controlling distance are valuable, and well worth learning, but the multiple club method is a great way for a beginner to start.
Pros can get shaft pured (or trued) for free. For them, it probably is as much placebo (peace of mind) as actual benefit.
The average golfer has enough wobble in his or her swing that the puring may not deliver that much benefit.
At the GolfWorks school, our instructor said that quality improvements in shaft manufacturing have made puring less useful (unless you get a bad batch of shafts). That said, he showed us a manual method for puring: You put a ball-bearing ring inside a vice, and insert the shaft through the ring, and spin it. The shaft heavy side will fall to the bottom. You then mark it and insert it accordingly.
I'm recalling the process from memory... sorry so sketchy.
On some graphites, however, we couldn't really find a heavy side.