some people are genetically "gifted" in that they seem to recover fine without PCT. I know someone at the gym who is that way, and have talked with him about it. While Matthew is right regarding most people, I think some can actually do without PCT.
NOW AFTER SAYING THAT....the percentage of people who might be able to skate by without seems very low, and the only way one would probably know that is if they tried cycling without PCT. And if your not one of the "lucky" ones, your screwed.
So my Advice for anyone is simply do PCT as you dont know how your body will respond. Also, while you make recover fine (and get lucky) after 1 cycle, it might not be the same case the next time. Since post cycle supps are so relatively cheap, and the goal of any cycle is to maximize the pros and minimize the cons...there is no reason for any sane individual to not use PCT.