I started with one pin. When I got my new bow & sight it had 5 pins. I just started shooting, and was having one heck of a time adjusting to all the pins. Finally, I took all but one out and what a difference. I have been shooting great (with other adjustments, too).
I was thinking of putting one more in for 30 yards and did the other day. I don't know if it will stay. I really don't like the 2 pins in my peep. Like someone said - just more clutter. I feel I'll go with 1 pin for 20 yds. and aim about 9" high for 30 yds. (that seems to be the drop) if I ever get a decent 30 yd. shot (probably won't ever take one).