When a lawsuit is filed, the parties must comply with statutes and rules pertaining to "discovery," motions, hearings and trial. The location of the court and sometimes the level of the case determine which statutes and rules shall apply. Cases involving greater amounts of money, numerous parties and/or many issues may be regarded as being of a higher level than cases that do not reach the same numbers. 

A great timetable for California cases: Noah Schwinghamer, Civil Law Time Limits - A cheat sheet for California Lawyers.