Inside a term, refinancing early to chase a lower rate usually triggers a prepayment penalty, so the strategy only works cleanly with a variable rate or at renewal. CMHC's insured-mortgage rules do not change mid-term just because rates move, so a mortgage broker can model the penalty against the savings before you commit to breaking a term early.
The appeal in a market like Saskatoon's, sitting at 1.63 months of supply, is locking in a home now while inventory is available, then managing the rate separately over time. You are buying the house today and treating the financing as a decision you keep revisiting.
Talk to a mortgage broker about your specific term before assuming this saves money. Get your hand-reviewed valuation from Joel Dyck.