I'm a Nurse, I was taught to aspirate at first, but, then once you know your sites, it's not obligatory. I give about 30 injections/ week to psychiatric clients of both fast acting and depot anti-psychotics, and have NEVER hit a vein. It's very difficult to hit one in the glutes, quads and delts which are "traditional" injection sites. However, when spot shootin...I strongly recommend it. I'm not saying not to aspirate, but, it's not a common practice in Nursing.