Atomizers are frequently used today; however, like any other pesticide-applying equipment, they must function properly so that pesticides can be applied correctly and precisely. When it comes to older machines, one might often encounter faulty devices. By testing various atomizer possibilities – where pump flow emerges as the most important – one would like to claim that the pump flow and the machine age might affect its working quality. Some tests have been done in Slovenia in the Šentjur School Centre with 30 tractor-mounted atomizers. Various equipment was used, such as manometers, gauges, flow measuring devices, hoses etc. This was extremely helpful since exact results had been measured and analyzed. Testing was conducted on Agromehanika and Zupan devices. Agromehanika atomizers, while tested, used a BM 2 and a BM 65/30 pump, while Zupan atomizers had the BM 2 and AR 30 pumps. These thirty atomizers checked pump flows, machine age, its capacity as well as all other important qualities a properly working device has. After these test, a conclusion was reached that old machines do not always affect the working quality, under the condition that the machine is properly serviced. On the other hand, pump flow does influence the atomizer working quality, because if the variance between the measured and the named pump flow is too big, exaggerated pesticide application occurs or plantations are not covered efficiently enough. Therefore, one can conclude that pump flow and machine age, as well as the good working order, can significantly affect the expenses while using it.