One consideration that is of primary importance is the intended application, with special emphasis on the environmental exposures throughout the life of the product. The prime decision whether to use wax, wax/resin, or resin ribbons is a cost/performance issue based on the needs of the application.
Moyer spells out the general spectrum of this cost/performance equation. "General purpose wax ribbons offer broad performance characteristics to deliver the image quality and durability required for most applications, while providing an excellent total cost solution. … Wax/resin ribbon products produce superior results across a wide range of applications at a lower cost than all-resin ribbons. These include a darker image, ability to print at higher speeds, less printhead static, and suitability with a wide range of media from paper to low-end synthetics. Specialty resin ribbons provide enhanced image quality and durability for applications that require special performance characteristics such as extra resistance to environmental conditions, smudging, or scratching. Grades are available that resist solvents, chemicals, and exposure to damaging UV rays."