A proper comparative market analysis is a short, defensible argument. It uses homes that actually sold, ideally within the last ninety days, of similar type, age and size, in your own neighbourhood, and then adjusts up or down for the differences. An appraiser holding a designation from the Appraisal Institute of Canada does the same thing under a formal standard for a lender. An agent's opinion is not an appraisal, but it should be able to withstand the same questions.
The uncomfortable part is that some valuations are a sales tactic. Quoting a high number to win a listing is an old habit, and it costs the seller, because an overpriced home burns through the first few weeks of buyer attention and then sells for less than a correctly priced one would have. With Saskatoon at 1.63 months of supply, there is demand for well priced homes and very little patience for the others. Since seller closing costs run 4 to 6 percent of the price, an inflated number also wrecks your planning for what you will actually net.
The valuations that hold up are the ones built in the house rather than at a desk. Online estimates and public records cannot see a renovation done without a permit, so any number produced from data alone starts wrong. Joel Dyck's hand-reviewed valuation walks the property, documents the improvements, and shows you the comparables and adjustments so you can judge the reasoning rather than just the figure.