“…Initially, all observations of the functioning of machines and devices are performed by operators during their normal work, such as watching the instrumentation, day-to-day checking of predetermined elements with the use of physical effects such as smell, sounds, vibration, temperature, sight observation, changes of appearance, necessity to apply force etc. Then, after training, the operators perform inspections on their own, take full responsibility for the inspections, maintenance, cleaning, adjustments and small repairs [13,24].…”