Why is there no “Due date” in Purchase Quotes similar to that in Sales Quotes? The practical use is simple to help with reminding when to follow up with the Supplier and decide if to Cancel the request.
I believe the philosophy is: if Manager does not do any thing with the data then you implement it via a custom field, sorts and custom reports.
There is also a philosophy that deals with consistency between similar interfaces. If it exists in one then there should be no need for it to be absent in a similar other one and requiring custom fields. Also custom fields do not change colour on overdue dates, it doesn’t track them.