I've got 12 cameras, setup to delete files > 21 days old. I believe my cams are setup to snapshot about 5 times per video recording. Usually run around 20k - 30k files. If I get rainy/snowy/foggy nights/days the cameras trip like crazy and I will see up to 60k files. Sunny, non-eventful days and I'll run around 15k files. Most of the files are from the transition between night-day and the camera trigger MANY times until the shutter stabilizes.
Hope this is what you were looking for.
