The turnaround depends mostly on how complete your file is at submission. A straightforward salaried applicant with documents ready can hear back quickly, while a self-employed borrower needing two years of tax filings verified will generally take longer.
The 90 to 120 day window matters most in a market where rates move, since it locks in the quoted rate while you shop, but it does not lock in the property itself, so a house still has to be found and an offer accepted within that time.
Once financing is in place, the clock shifts to finding the right house at the right price. Get your hand-reviewed valuation from Joel Dyck.