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This depends on the type of case. While no California statute expressly governs client file retention, ethics opinions and accepted practice has worked out the following standards:
CRIMINAL CASE - life of client
JUVENILE DEPENDENCY CASE - "substantial period" if not life of client
PROBATE CASE - unclear, perhaps at least 5 years
TRUST CASE - unclear, perhaps duration of trust and at least 5 more years
GENERAL CIVIL - unclear, perhaps at least 5 years.
See more HERE and HERE.
NOTE that the above are subjective time frames. Because no specific rule exists (the closest official rule is the criminal case for life of the client), whether or not the attorney erred by disposing of the file would eventually be up to the Bar, the Court, or another authoritative body.
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