It took me about 2 years, starting at age 25, to acquire perfect pitch. I didn't try the Vai trick, instead I ran an exercise at last once every few days that c

It took me about 2 years, starting at age 25, to acquire perfect pitch. I didn't try the Vai trick, instead I ran an exercise at last once every few days that challenged me to name the note associated with a tone (out of all 12 equal-temperament tones). At first I got right about 20% of the time, but I was able to get to 100% over those two years. But long before I could complete the exercise, I was able to tune my guitar perfectly, and I can still tune it fine in a very loud environment, or on stage without the full ability to hear it myself. After playing it for long enough a good guitar made from good tone-woods will resonate like a bell around the "home" frequencies you play a lot. For me, in DADGAD tuning that's a "D" that makes the rosewood echo, but the "A"'s are plenty strong too. If it's out by even a few cents, the guitar just plain doesn't feel right.