Thank you for sending and offering to provide the response. Below is the answer based on NSRP Standards of Practice. Feel free to email him and also provide a brief answer by phone (if you are corresponding by phone with him)
For clients who were adults at the time of last contact with them, their files should be kept for 10 years.
For those who were under the age of 18 when seen by the psychologist, their files should be kept 10 years following the date of the client’s 18th birthday. Here is the link to and quote from 7.4 of the Standards of Professional Conduct:
https://www.ns-rp.ca/downloads/Binder_Standards_Legislation_Guidelines.pdf
“Unless otherwise required by law a registrant shall retain both individual and corporate client records for at least ten years following the last client contact. If an individual client was less than eighteen years of age at the time of last contact, the individual client record shall be retained for ten years following the date of the client’s eighteenth birthday…”