Things I learned the hard way:
A 30 year old blade with correct lies is easier to hit then a GI CB that's bent 2 degrees the wrong way. I play 2 deg toe down, more people play 2 deg toe up. I keep an old Sam Snead 6 iron that's set up correctly for me and take it with me when trying out clubs.
Sometimes I have an iron I can't hit worth squat. When put on a frequency analyzer the problem turns out to be the shaft.
A SW I was splaying balls with made figure 8's.
Brand new out of the box clubs from a major manufacture of good reputation doesn't guarantee the lofts and lies are even.
Shafts marked A, R, S can be the same flex. There's no standard and the only way to know is to have them tested. (Should be done free along with checking loft/lie when buying new.) About $25 for used clubs.