Why do I have to reset my password every 90 days?
Every 90 days, BigCommerce will prompt you to reset the password you use for logging into your store. The primary reason for this frequent reset is to make sure that your account information is secured. It is also a requirement to be PCI (Payment Card Industry) compliant.
This specific requirement is outlined in Requirement 8 of Version 3.2 of the Payment Card Industry Data Security Standards. See PCI Compliance Password Requirements for more details.