A Roll End Tuck Front will take approximately 30 seconds to 1 minute to assemble, depending on the size and experience of the person assembling the box. Once several have been assembled, each person develops their own technique for doing it quickly and can do it quite rapidly.
Some products look best displayed in a RETF and wouldn't be something you could compromise brand identity for the cost savings of a different style. However, many people choose to start off with a RETF style box when the volume is fairly low as it is one of the more economical box styles. As demand increases and/or if a production line is implemented, you might want to consider an auto forming box that requires less time to package and seal by hand and can also be formed and sealed by a machine.