Common methods to assess hearing deficits and the benefit of hearing devices include retrospective questionnaires and speech tests under controlled conditions. As typically applied, both approaches suffer from serious limitations regarding their ecological validity. An alternative approach rapidly gaining widespread use is ecological momentary assessment (EMA), which employs repeated assessments of individual everyday situations. Smartphones facilitate the implementation of questionnaires and rating schemes to be administered in the real life of study participants or customers, during or shortly after an experience. In addition, objective acoustical parameters extracted from head- or body-worn microphones and/or settings from the hearing aid's signal processing unit can be stored alongside the questionnaire data. The advantages of using EMA include participant-specific, context-sensitive information on activities, experienced challenges, and preferences. However, to preserve the privacy of all communication partners and bystanders, the law in many countries does not allow audio recordings, limiting the information about environmental acoustics to statistical data such as, for example, levels and averaged spectra. Other challenges for EMA are, for example, the unsupervised handling of the equipment, the trade-off between the accuracy of description and the number of similar listening situations when performing comparisons (e.g., with and without hearing aids), the trade-off between the duration of recording intervals and the amount of data collected and analyzed, the random or target-oriented reminder for subjective responses, as well as the willingness and ability of the participants to respond while doing specific tasks. This contribution reviews EMA in hearing research, its purpose, current applications, and possible future directions.