Sustains at the End of Film Cues
You should always make sure to have long enough last chords/sustains in film music cues that are supposed to “vanish” into nothing as the fade-out time needed might be longer than you think. If you end too early, the fade-out might be too quick and too obvious for the situation as the purpose of fade-outs is to be un-noticed.
Therefore, make sure to rather record too much of the last chord/note than too little. It is easier to fade out a too long sustain early than to edit a too short last note so it sustains longer.