Where do you draw the line between ugly and illegal?

[DaveASA/FED]

I had a game last night that made me once again wonder this. It was a lower level middle school match, I was up for the 7th grade match, there were several hits that could have been called illegal, about 3-4 for each team. There were 4-5 that I did call during the match, a couple for each team. With the match 23-17 team A hit a ball at the net that the coach of team B wanted called illegal, it looked questionable to me but not accross the line I was calling that game. I guess my question is this, I have always been more leanant at the lower levels as they are just learning and don't want to discourage them. And then I tighten up as I go up in level. I guess I am looking to see does everyone do this? Or do you use the same illegal hit criteria from 6-12 grades? And if you do loosen up, what do you use as your ugly line? You know the line where it is too ugly to let go and you have to call it?? I know these are subjective had to be there calls, but I guess I am just looking for some general ideas how you all call this. Thanks.