Where a specific day count does show up in a Saskatchewan purchase is in the conditions a buyer negotiates: financing and inspection conditions commonly get 10 to 15 business days to be removed, and possession date is a separate, negotiated calendar date rather than a fixed window tied to occupancy.
Occupancy requirements do show up on the lending side: an insured mortgage through CMHC generally expects the home to be owner-occupied, and a lender can ask questions if a property purchased as a primary residence is immediately rented out instead, but that is a lending condition, not a fixed 30-day rule.
The safest approach is to read the actual conditions in a specific offer rather than assume a rule imported from somewhere else. Get your hand-reviewed valuation from Joel Dyck.