Ok I know how hard it is. You will learn to recognise when a chick needs your help. Chicks do peep the day before they pip though- I suspect your temp is a little low and they will hatch in 22 days. This is my experience hatching many eggs:
I have never had a chick die because it was unable to pip, if this is the case it probably has a serious beak deformity and perhaps your temperature is too high. Don't help it- you'll only have to put it out of its misery /: If it pips, but is unable to break the shell further, and you notice the white skin inside the shell is looking thick, opaque and rubbery, your humidity is too low and you should wait a day then help it out. Wait a day because it might only be paused while it absorbs it's yolk sack (the white sack has blood vessels in it until the yolk is absorbed). Don't try to raise the humidity drastically at this point- it wont help, and you could drown the rest of them. If your temperature is too low, it could take up to 23 days to hatch! Some chicks could be born with unabsorbed yolks, but overall your hatch will be ok, just late...don't help them out. Too high humidity will drown your chicks in the egg, you will see fluid oozing into the air sack when candling. Hmm thats all I can think of. Oh some breeds hatch a bit later than others (araucanas, cochins..probably others). Patience!