I learned this fact when I was lucky enough to have an addict as the very first patient I ever drew blood from. Unlike the rubber arms we practiced with in the phlebotomy class provided by the hospital, she did not have multiple punctures in her arm indicating exactly where to stick the needle. She was, however, kind, patient, and instructive. Sure, I was a little weirded out when she sighed and claimed the latex tourniquet "felt good against her skin," but she claimed it was only because she'd been clean for six months and missed the sensation of shooting up. While basking in the memories, she pointed out different veins that a very nervous new ER tech could try, showed me angles to go in at, and offered tips on how to find veins on tough sticks. Thanks in large part to her help, my first attempt at drawing blood was a success.
Flash forward a year and a half to last night, a busy Monday, where I was drawing labs at triage in an effort to speed up patient flow. Real Friendly Addict rolled up to the desk in his wheelchair, and under the guise of "Hey buddy, let me show you where the good ones are," kept pointing me to heavily scarred, overused veins. Playing along, I kept searching the arm until I found a small but juicy one above the elbow, and struck with my butterfly.
Real Friendly Addict quickly turned into Pissed Off Addict and screamed, "Hey, I was saving that one!"