Trying to make that judgement call is a tough one.
I had an egg pip at the wrong end and chirp really loudly for 16 hours. He made no progress at all, but he sure was vocal about it. When his peeping started to quiet down I made the decision to help. He was in the wrong position for getting himself out of the egg, not to mention, he pipped at the wrong end. I know he would have died had I not helped.
The next batch, I had 2 eggs that pipped at the wrong end, and one of those pipped underneath. I waited 36 hours to help those guys. They were trying, but making very little progress. Both of those helped babies died within 3 days of hatching. It was heart-wrenching for me...I gave them vitamins, tried to force feed and water them, they just were not thriving.
I wondered what the difference was, and you know, both of those chicks that didn't make it weren't vocal in the eggs. Sure, they were trying, but they weren't peeping.
I don't think they were meant to hatch, and helping them caused me huge guilt and heartache.
In the same position again, I'm not sure what I would do.
But I think, for me, if there was no pip, I probably wouldn't help.