Disability Tax Credit makes you eligible for more claims
When adjusting for prior year claims for Disability Tax Credit (DTC), make sure you check your whole return and that of your spouse/partner each year.
It may be possible that your return may be adjustable for other claims not previously possible without the DTC. There are various medical expenses that require the DTC and when you become eligible for the DTC, you also become eligible for those claims for therapy, respite, attendant care...etc.
Child care expense claims may increase as a result of qualification for the DTC. In 2007:
The limits for a child for whom the disability amount can be claimed increase from $7,000 to $10,000 if born in 2007 or earlier.
If born in 1990 or earlier with a mental or physical infirmity for whom the disability amoutn can not be claimed, $4,000.
If you did not submit receipts for more than the usual limit, or even if you did submit receipts, but did not claim the increased amounts, it would be necessary to request an adjustment.
You can't rely on CRA staff to provide an automatic adjustment. If you don't ask for it, you won't receive it.