During the rehearsal process, the stage manager's most important role is to record all of the blocking, lighting cues, prop usage, costume changes and entrances of all the performers. This usually requires shadowing the director and taking copious notes. A stage manager is also responsible for scheduling rehearsal times and making sure those times are respected. During rehearsals, it falls on the stage manager to make sure understudies have sufficient time to learn their roles in case of an emergency. The stage manager is also bound by theater tradition to supply the daily coffee before rehearsals begin.
On the day of the live performance, a stage manager may have to deal with both technical and human crises. An actor may not be able to perform due to illness, or a crucial prop may disappear. A good stage manager must learn to think under pressure while maintaining some semblance of order and timeliness. Actors often depend on a stage manager or an assistant to count down the time until the curtain rises. Indeed, it is the stage manager's job to issue the familiar call of 'Places Everyone!' shortly before the performance begins.
During the performance, a stage manager might also be responsible for cuing the lights, sound or scenery changes. Notes for all of these cues are often contained in a notebook, which inspired the theatrical description of a stage manager's job - "running the