Adjusting hearing aid user's real ear performance by using probe-microphone technology (real ear measurement, REM) has been a well-known procedure that verifies whether the output of the hearing aid at the eardrum matches the desired prescribed target. Still less than half of audiologists verify hearing aid fitting to match the prescribed target amplification with this technology. Recent studies have demonstrated failures to match the prescribed amplification targets, using exclusively the predictions of the proprietary software. American Speech-Language-Hearing Association (ASHA) and American Academy of Audiology (AAA) have created Best Practice Guidelines that recommend using real-ear measurement (REM) over initial fit approach and also the recent ISO 21388:2020 on hearing aid fitting management recommends the routine use of REM. Still audiologists prefer to rely on the manufacturer's default first-fit settings because of the lack of proof over cost-effectiveness and patient outcome in using REM. There are only few publications of varying levels of evidence indicating benefits of REM-fitted hearing aids with respect to patient outcomes that include self-reported listening ability, speech intelligibility in quiet and noise and patients' preference. Our main research question is whether REM-based fitting improves the patient reported outcome measures - PROMs (SSQ, HERE) and performance-based outcome measures (speech-reception threshold in noise) over initial fit approach. An additional research question is whether REM-based fitting improves hearing aid usage (self-reported \& log-data report). Eventually, the investigators will calculate the cost-effectiveness of REM-based fitting.