The number of patients suffering from obstructive lung diseases is increasing. A long-acting inhaler is the mainstay of their treatment. Here, inhalation device operation maneuver was assessed by community pharmacists and evaluated in relation to patient characteristics. Subjects were gathered from our clinic from May 2014 to July 2017. The inhalation procedure comprises seven steps. Based on the patient's mastery of the step, each step was evaluated on a scale of 0 to 3 points, then the total number of points was added up. Correlations were calculated between total procedure evaluation points and patient characteristics. Prognostic evaluation was analyzed by the time to the first exacerbation episode after receiving instruction. The median of total evaluation was 20.5 [11.6–21]. Group comparisons showed a worse performance in males, chronic obstructive pulmonary disease (COPD) patients, and low Karnofsky performance score patients. Prognostic analysis revealed a statistical significance in women (p=0.01) and those with lower Brinkman index (BI) (p=0.04). Patients with particular characteristics tended to have difficulty with inhaler maneuvers, while the patients that had a better technique still had the potential to experience exacerbations.