Do I NEED to prime it?

On many occasions I have started engines hat have been sitting for unknown periods of time without worrying about priming them, never had any problems. In most of those situations I was hoping for a good outcome, but if the engine had been pooched, it would not have been a big problem. In this situation, I would not be willing to risk the investment in a newly built motor to impatience. I suggest either make a priming tool out of a old shaft if you have one, or go and buy or borrow one. How much longer will you be waiting if it goes bad before you can get your car running?