California licenses must renew every two years.  Title 16 CCR section 4161(a)
 
Occupational Therapist
24 professional development units (PDUs) every two-years.  Title 16 CCR section 4161(a)
 
 
Occupational Therapy Assistant
24 professional development units (PDUs) every two-years.  Title 16 CCR section 4161(a)

For more information visit the California Board of Occupational Therapy