I dont think you have much choice in when you get it. Its all about when dr says and when they get to you unless you are asking them to wait then you may have a choice in it. I have heard of a lot of people it wore off on felt everything at the end. And i have heard of a lot of people not getting it in time.
I agree with the above statements. The perfect time is when they offer it to you, which they generally do if they know it's a part of your birthing plan (so make it known). If you can handle the pain then be honest... if it's getting bad... be honest. I've always held off until the very last moment. With 3 children only 1 of the epidurals didn't cover the pain of actual labor. I was watching monitors for contractions to begin and then I'd push. I found it easier with all 3 to push against my contractions... thus covering a majority of any discomfort. My 2nd child the epidural was so great I didn't hear the doctor tell me to stop pushing so he could flip my son, which resulted in a bigger tear. Just listen to your birthing team (all those crazy people in the room) and you should be fine. As for "when" i think it depends on your progress entirely. I would just make it known that it IS infact part of your plan because some women don't mention it and I've heard once you get too far along they can't give you it anymore. I believe I always gave in around 6cm. Good luck :)
Often doctors will let it wear off on purpose so you can push. When the epidural is in full effect, you can't feel what you're pushing and can't effectively get the baby out.
I know u feel pressure which can be painfull
Not sure how it worw off whwn its a continuous drip until after u have the baby and the after birth... But they wouldnt let me until I was four centimeters and that was after my pain meds had worn off and then I dialated from 4 to 10 in 10 mins