What ānon-refundableā means
The DTC reduces income tax payable. If the credit is greater than the tax owed, the unused amount is not paid out as a cash refund simply because the credit exists. An eligible supporting family member may be able to use an unused portion under the applicable rules.
Why past tax years can matter
A review may identify tax adjustments for eligible prior years. The relevant approval period and tax history affect the result. A particular refund amount is not guaranteed.
Approval can open other doors
DTC eligibility may also be relevant to programs such as the Registered Disability Savings Plan, Child Disability Benefit or Canada Disability Benefit. Each program has additional requirements.
Read the official CRA explanation