You have a limited amount of rehearsal time, and no one really knows if it’s going to be enough or not. Don’t waste any of it. Get to rehearsal early enough that you can take off your coat, change to your rehearsal shoes, get out your script, turn off your cell phone, and gather your bearings. If you need to eat when you get to the theater, get there early enough that you’ve finished swallowing by the time rehearsal is to start.
If everyone arrives at the time the director has called for rehearsal to begin, the odds are very good that ten minutes will be wasted while everyone greets everyone else and gets their act together. It is courteous to get that out of the way PRIOR to the called time. If you don’t, then whoever IS ready to begin at that time has to wait for you.
Tech week is always difficult. If you can be early, that’s often a good idea, because sorting out technical issues always takes more time than you think. The earlier you get there, the earlier you can go home.
On performance nights, know when the stage manager has called you for and be there on time. No one wants to worry about whether or not you’ve had car trouble.
If for any reason you are going to be AT ALL LATE for ANY rehearsal or performance, call and let someone know as soon as you know, so that they can deal with your lateness appropriately.
If the schedule has been changed and you are no longer expected at rehearsal, confirm that with your director or stage manager. Some shows don’t really have a schedule, and what is being dealt with at future rehearsals is so fluid that it is easy for actors to get confused about when they are needed. So check and double-check about when you are required to be there!