The CDN citizen returning can bring personal possessions back to Canada duty free, the items have to be bought more than 6 months prior to returning home, I don't think there is a $$ limit of what can be brought. As mentioned above my understanding is an Immigrant who has not completed a GTF list that their possessions can be/will be taxed at fair market value. I think the biggest concern would be if you have a lot of valuables like jewellery, gold, paintings, etc. All the info should be available on Canada Customs web site. Start with this link:
https://www.cbsa-asfc.gc.ca/travel-voyage/mrc-drc-eng.html