Professional Indemnity (PI) insurance is different to most other insurances. PI is a 'claims-made' policy, meaning it only provides cover for claims when the policy is in force. The policy holder cannot lodge a claim on PI insurance that has expired.
No matter how good a physiotherapy practitioner you may be, things can go wrong. In the event that they do and you need to make a professional indemnity or medical malpractice claim, good patient records are crucial to the defence and timely resolution of the matter.