After reading others comments on volunteering at a trial, I thought I would add my own experience. Like others I found that I was always working and others were having a leisure and fun day with their friends and dogs. So I learned that I needed to balance my load and not agree to any time frame that would interfere with my own dog's runs. That is very easy to do in a 2 ring event but gets more difficult with 3. I have learned to say no if I need to which was very hard for me to do. I also tend to volunteer the day of rather than ahead of time, that way if a ring is running ahead or behind I can judge accordingly.
In my area there are A LOT of people that I never see in the ring helping but they sure do run their mouth about HOW the event is going. So I say, help out or be quiet!!!