What kind of eggs? Duck eggs take longer--usually 24 to 48 hours from pip to hatch. I don't know what is the max for chicken eggs, and I imagine different breeds are slightly different too. Check out the threads on helping--I think there's a sticky, and a search should unearth TONS of info. But basically, I wouldn't even dream of helping before 24 hours. After that, you have to look at the whole situation. Has the chick made any progress? Is it peeping loudly? Does it appear to have weakened? Etc. I would say that on a first hatch, it's better to wait and see than to jump in and try something, because you just won't know what "normal" truly looks like until you've seen it a few times. And you can easily kill a chick by helping too soon. Post more details and I'm sure others will have loads of input for you. Good luck!