For instance, if one were to find receipts between 2-3 years old, are they still useable? Is there a fee for a re-assessment?
The maximum period that you can refile an adjustment is 10 years prior to the year you ask for a T1 adjustment.
Only requests relating to tax years ending in any of the 10 calendar years before the year you make the request will be considered. For example, a request made in 2009 must relate to the 1999 or a subsequent tax year to be considered.
There is no charge for requesting an adjustment but if the refiling results in taxes owing then there may be an interest charge an amounts owing.