We use the AudioMoth with large batteries for long term bat monitoring. Our normal standard is 5 sec. recording 10 sec. pause. After some days the writing on the SD card is running slow. Typical after there is 35,000 files on the SD card. The result is that only every second files is saved. (Turn into 5 sec recording 25 sec pause). After 70,000 files is on the SD card the writing becomes even slower and the only every third or fourth file is saved. Batteries are ok, and there are plenty of space on the 128 Gb SD card. Interestingly the problems can be solved if we manually transfer the 35,000 files to a separate folder on the same SD card. It could be great if the setting could allow a daily folder or any other suggestion to solve the problem.