I've been told to come into the hospital when I'm having contractions 5 minutes apart for 1.5 hours (first baby, I'm in France).
What does that actually mean though? 5 minutes from start to start? From the end of one to the beginning of another? 
I want to try and stay at home as long as possible (the midwives telling us to make the labour room into a cocoon as we'll be there for 8-10 hours freaked me out somewhat!
) but obviously don't want to give birth at home (or worse, in a taxi...)