California Code of Civil Procedure
Subject to Sections 2025.270 and 2025.610, an oral deposition may be taken as follows:
(a) The defendant may serve a deposition notice without leave of court at any time after that defendant has been served or has appeared in the action, whichever occurs first.
(b) The plaintiff may serve a deposition notice without leave of court on any date that is 20 days after the service of the summons on, or appearance by, any defendant. On motion with or without notice, the court, for good cause shown, may grant to a plaintiff leave to serve a deposition notice on an earlier date.