This is a great question as most of the work in acquiring a loan is done prior to contingency removal: Appraisal, Conditional Loan Approval, and Inspections. Given the fact that it is feasible to complete a full loan now within 25 days or less, it is often just better to try to leave the loan contingency in until funding. Many Listing Agents don't pay attention to this and it is very nice to have in place. In addition, the stigma about about "until funding" can often be overcome with a larger deposit.
If you need a contingency period, then 17 days is fine and that is plenty. It is definitely exciting to go many fewer days as it can be a challenge to get a slower buyer to get disclosures completed, appraisal portal opened, appraisal ordered, and any issues handled that might come up that need to be negotiated.