Make sure your software does not lose data when improperly quit, and does not allow deletion without a proper confirmation dialogue.

I have experienced pre-installed voice recorder applications that leave behind an unsalvageable corrupt file if the smartphone shuts down due to running out of battery charge, or powers off due to battery undervoltage (as a result of an aged battery).

As often, third-party software beats pre-installed software, and the voice recorder "ASR" by "NLL apps" leaves behind a playable file when unexpectedly quit. Might be because it uses the OGG vorbis format rather than M4A or 3GP audio.

Also, the camera software of the Samsung Galaxy Pocket smartphone from 2012 (which was crap anyway) would discard a video file if the recording was quit through the "back" navigation key.
Perhaps this was done deliberately, but it is a terrible idea due to the possibility of accidents happening.

Some gallery software for Android lets the user delete photos and videos by swiping vertically. After this, a so-called "toast" notification appears with an undo button. If not responded to within seconds, or when tapping next to it due to stress, the photo or video is gone. This is, needless to say, terrible design.