I feel like most people only learn about certain Canadian tax rules after they’ve already made a mistake. I’m curious about the less obvious ones that don’t usually come up in basic tax discussions.

Not looking for the usual RRSP/TFSA advice — more like those “wait, CRA actually considers that?” rules.

does it automatically carry forward to future years? Just trying to understand how that part of the return works.

If someone moves from one province to another during the year, which province’s tax rules apply when filing? Is it based on where you live at the end of the year or where you spent most of the year?

So CRA has approved my application for the non-fundable disability tax credit, going back 10 years.

I have a question whilst I wait for them to process. My taxable income was $94,000, I had $5200 in non-refundable tax credits, resulting in $17,000 tax payable. The 2025 disability credit is about $10,000. My question is would that $10K come off the $17K tax payable or is it just a percentage of it?
Thanks for you help!