What is the essential condition for a successful rehearsal process?

Answers by: Wanda Golonka, Staffan Valdemar Holm, Heiner Goebbels, Lotte Van Den Berg, Jan Fabre, Stef Lernous, Franck Chartier, Gabriela Carrizo, Eugenio Barba, Signa Sørensen, and Jean Francois Peyret.