I haven't read through responses so I apologise in advance if I am repeating myself.

When you sit and watch and listen to a woman in labour she will "tell" you how far dilated she is. Unless for a medical reason there really isn't any good reason to be thrusting gloved fingers into a womans vagina during labour.

Having said that - when there is a lip this can be flipped over during a contraction and can save more invasive procedures. So there is a place for it if an anterior lip is believed to have happened.

I have only ever had one VE during labour with my fourth and it hurt like hell! I asked for it as I wasn't progressing as quickly as I thought I should... Anyway I was 7cms - very depressing for me. With the next contraction Eva was born. Soooo...

Anyway - I believe watching and listening are the best "crystal balls" to how a labour is progressing.