The duty of communication is both a fiduciary duty and, for lawyers, a professional one. American Bar Association Model Rule 1.4, one rule that every jurisdiction has adopted nearly verbatim, holds that
(a) A lawyer shall:
(1) promptly inform the client of any decision or circumstance with respect to which the client’s informed consent, as defined in Rule 1.0(e), is required by these Rules;
(2) reasonably consult with the client about the means by which the client’s objectives are to be accomplished;
(3) keep the client reasonably informed about the status of the matter;
(4) promptly comply with reasonable requests for information; and
(5) consult with the client about any relevant limitation on the lawyer’s conduct when the lawyer knows that the client expects assistance not permitted by the Rules of Professional Conduct or other law.
(b) A lawyer shall explain a matter to the extent reasonably necessary to permit the client to make informed decisions regarding the representation.
The last part is, much of the time, a fictional standard. I have been hammering at this in my recent ethics seminars, much to attendees alarm: clients often, perhaps even most of the time, don’t comprehend what’s going on on many levels.