Asthma and chronic obstructive pulmonary disease are common chronic respiratory diseases. The foundation of pharmacological treatment in both diseases is the use of inhaled medications. Treatment outcomes depend on selecting the appropriate active substance as well as an inhaler that is suitable for the individual patient. Patients who make errors in the inhalation technique have poorer disease control. The need for regular assessment and training in correct inhalation technique is emphasised in the GINA and GOLD reports. Due to anticipated financial and environmental benefits, switching inhaled medications is sometimes recommended. The aim of this article was to analyse the benefits and drawbacks of switching inhalers for non-clinical reasons. Literature data show that inhaler switch can lead to poorer disease control and more frequent exacerbations and hospitalizations, and it may also negatively affect the patient–healthcare professional relationship. Moreover, any expected economic benefits of switching inhalers may be outweighed by the costs associated with worsening disease control due to improper inhaler use and reduced adherence. Any change of inhaled therapy should therefore be driven by medical factors.