The City of Saskatoon inspects a secondary suite for egress windows, ceiling height and fire separation, often requiring a separate entrance, before it counts as legal. A beautifully finished basement with a tenant paying rent every month still fails a lender's test without that permit on file.
Even with a permitted suite, a lender typically counts only a portion of the documented rent, not the full amount, when weighing it against CMHC's guideline of roughly 39 percent of gross income on housing costs and 44 percent on total debt, so the income helps but rarely covers the second unit's full carrying cost on paper.
An unpermitted secondary suite is exactly the kind of improvement an online estimate cannot see, which is why the real number is worth getting right before you offer or list. Get your hand-reviewed valuation from Joel Dyck.