Instruction has progressed toward a myriad of technologies, many times in conjunction with each other, to teach students and techs, whether the instructors and students are in the same room or not.
Technicians need to to be aware that ice machine servicing expertise might be just one small part of the technology they could encounter on a single piece of refrigerated equipment.
Developed countries have refrigeration systems that protect food until it is delivered to customers. But, in developing countries, that refrigeration aspect is often missing at almost every step along the cold chain.