Not for DC1
DC2 I hit 4cm and the pain ratchet up so fast it was frightening. Epidural time.
Originally intended to keep feeling in legs but when anaesthetist tried to insert he hit bone 
So went to back up position which is higher. I couldn't feel my legs really. I knew contractions were happening and the big ones, I could faintly feel some pain, but it was bliss. I rested. Husband was able to get some sleep too.
At my hospital, they let you keep up the button pressing until you get to 10cm. Then ask you to stop pressing the button for an hour before pushing.
I'm surprised a few PP had problems pushing, because for me I was able to be so much more focused at pushing with the epidural than I had been without.
Each push felt 100x more effective and I felt a LOT more in control than I had without for DC1 (totally drug free). Bare in mind, I'd been in pre-labour for about 4 weeks, active for 23hrs by this point. I felt fully awake & aware of my surroundings.
Baby because a bit distressed (nothing to do with epidural) and because I was so mentally "with it" I managed to double down and get him out fast (not too fast) and without intervention.
I'm not having any more babies, but if I were I would absolutely have another epidural. Bloody miracle things.