The answer to this question depends on how you plan to display the flags. Single sided flags work well if they are on display at a distance. In addition, it helps if the message is simple like “SALE”, “OPEN” or Branding. The single sided option works well along roadways and driveways. Especially, when drawing attention is the primary goal. If prospects are up close or will the flags include detailed information. A double-sided printing option may be your best option.