Yeah that's true.
My 30 hour one wasn't too bad til about 9 hours before DD2 was born. When the contractions got regular. They were half an hour apart when I decided I couldn't bear it any more. They'd been half an hour apart & getting more painful for 3 hours. I was terrified that if they were that bad at half an hour apart I'd never survive when they got closer!
When I got up & woke up DH they hit me 5 minutes apart. We went up to the hospital - 40 minutes of agony! - to find out that I was 6 - 7 cm dialated. I was only at the hospital for about 4 hours before I had her.
I got through with no pain relief!