## 1 Introduction  
A cochlear implant (CI) is a prosthetic device for the inner ear that directly stimulates the auditory nerve, bypassing damaged inner hair cells and generating audible sensations, even in cases of profound deafness. Current CI systems generally provide effective speech perception in quiet environments [1, 2, 3]. However, challenges arise in more complex acoustic environments, such as those with background noise or reverberation, where many users face difficulties in understanding speech [4, 5, 6]. One of the critical factors influencing speech perception is the adjustment of the sound processors. The correct determination of threshold levels and upper stimulation limits is a pivotal aspect in this adjustment process [6]. Typically, the fitting process for a hearing aid (HA) or a CI is highly individualized. An initial fitting is typically performed by an expert. Subsequent fine-tuning is based on the expert's expertise and the user's feedback. The fine-tuned HA or CI is then worn by the user in various real-life listening scenarios. Further appointments for fine-tuning are commonly necessary, and this iterative process continues until a satisfactory setting is achieved for the user [7, 8]. As a result, this fitting process may span several sessions, and the final configuration is heavily influenced by the expert's experience and the time spent with the patient [9].  
One potential solution to these problems is allowing users to adjust their hearing aid (HA) and cochlear implant (CI) settings themselves. This self-adjustment in everyday situations could enable users to tailor the sound to specific hearing environments, thereby enhancing their auditory experience. The concept of self-adjustment has been exploredby various research groups. Notably, [PERSON] et al. [7] investigated this approach for hearing aids, while [PERSON] et al. [6] and [PERSON] et al. [10] examined its application for cochlear implants. They showed that self-adjustment led to a higher satisfaction in different acoustic environments but not to higher speech intelligibility. In both studies, users began with an expert baseline setting and could amplify or attenuate specific frequency ranges of the input signal using a software tool. Building on these findings, [PERSON] et al. [9] introduced a self-adjustment function for bimodal users via an app in 2023, leveraging the latest generations of cochlear implants and hearing aids with integrated Bluetooth. The primary aim of that study was to evaluate the usability of two distinct UIs, one featuring a traditional equalizer and volume control, while the other one employed a 2D surface approach. Regardless of the UI type, both interfaces allowed users to modify the sound parameters of the CI and HA. The study also aimed to compare hearing outcomes based on patient adjustments. Previous data showed that in 80% of all tested conditions, participants preferred their self-adjusted settings over the expert fitting [9]. The current study examined how the findings obtained under laboratory conditions correspond to data and subjective impressions collected in real-life situations. Additionally, it analyzed user behavior and individual adaptation practices in daily life. A total of 15 study participants, including both bimodal and bilateral cochlear implant users, were provided with a self-adjustment app that they integrated into their daily lives over a period of six months. Data on app usage, adjustments, and prevailing daily life situations were collected and analyzed throughout the study period. Two of the fifteen participants withdrew from this study early, as they did not perceive any personal benefit from the opportunity for self-adjustment in their daily lives.