There are three main types of inhalers, dry powder inhalers (DPI, single and multidose), metered dose inhalers (pMDI, spray, suspension and solution), and soft mist (SMI). There are major differences in inhalation technique and handling of the different inhaler types. Different inhalers are well suited for different patients and the choice of inhaler may be crucial for the treatment outcome. It is frequently observed that patients have poor inhaler technique and the use of different inhalers, in particular inhaler types, in the same patient increases the risk of handling errors. Careful instructions and follow up on inhaler technique at every visit to the health care center is of utmost importance. In treatment failure, change of inhaler may be considered before change of drugs or dosing. Change of inhaler as a result of a telephone prescriptions is unacceptable and must not happen.