Hi zinergy
Some guys tend to get pip when they're injecting short esters like propionate. Is that what you're using?
I rarely aspirate myself. This is only because I've been self injecting HRT for 12 years and like to think I know my around my body and how it reacts etc.
However, if a person is new or relatively inexperienced with self injecting, then I'd highly advise them to aspirate each and every injection. Aspiration is also a must do if you think you might have plunged into a vein. Basically, wherever there is doubt, draw it out.