bro, as cheap as pins are, i personally use a new syringe and 2 pins on every inject for every compound. so, if i'm stacking test and Deca-Durabolin - nandrolone decanoate - , i'd use up two syringes and 4 pins to get the job done. 2 of the pins are for drawing it from the vial, the other two are for pinning. i like it this way, it gives me an accurate dose, and dammit......i just like it that way. i know guys, if they are both oil based it doesn't matter, but i'm OCD as hell ok, so give a brotha a break. sheesh! LOL
ps- i seriously do use 2 pins with one syringe per compound, and i never mix em. that's just how my seriously OCD old ass does it.