Final answer:
Mail carriers pick up and sort flats according to the operational standards of their postal authority or company, considering factors like route size and mail volume.
Step-by-step explanation:
The question 'How much mail should a carrier pick up when casing flats?' is related to procedures within the postal service or a mail distribution center. This is typically part of on-the-job training or an operational guideline set by a postal authority or company.
Generally, a mail carrier is expected to pick up and sort an amount of flats (large envelopes, magazines, and similar items) in line with the company's operational standards, which may consider factors such as the size of the route, volume of mail on a given day, and efficiency methods for sorting and delivery. Detailed instructions would be provided during training or within an employee handbook specific to the organization.