Markers are useful for more than just production. Sample markers during the development process can help you plan and make adjustments as needed. Primarily, they help you figure out how much fabric is needed to make the garment.
Beyond yields, they can reveal ways that the pattern can be made to fit the fabric more efficiently. Sometimes an extra seam can be added or the sweep of a full skirt can be adjusted to fit the fabric better and eliminate as much waste as possible.
A sample marker can also help determine the optimal fabric width. I recently ran some marker tests for a client who is getting fabric custom developed and wanted to know if a few extra inches of cuttable width would improve the yield of their styles or if it would just result in wasted space.
Have you ever used sample markers to reveal information about your designs and patterns?