It depends on the policy of the application. Applications are broken down into enhanced policy and standard policy.

• If the application uses the Standard security profile, you will only be prompted to authenticate with Duo once every 24 hours, if you choose to trust the device that is accessing the U of T application.
• If the application is protected by the Enhanced security profile, you will be prompted to authenticate with Duo every single time that you log in. Additionally, if you are not enrolled in MFA, you will be denied access to the U of T application.

Please refer to KB0015004: UTORMFA security profiles for more details on the application categories.