It is a challenge when they have to do blood draws from the same arm all the time. Like some of you, I have a big knot, probably scarring, on that side and it can be a challenge. I usually tell them they can use any vein on my left arm they think they can hit in one try. I've learned that drawing blood takes skill. It's an art. Some people can't hit the vein no matter how many tries. I have others that hit the vein in two seconds, every time, no problem. If they start feeling around too long before the needle, I know it's going to be a problem. Ironically, the techs at the labs are the worst shots. The radiology techs that put in contrast are not so great at putting in ports either. I sometimes tell them they get one shot then I want someone else to try.