Thank you petrolhead first actually answer. I totally agree with the extra frames (25fps) it's easy to lower but you can easily miss the frame with the impact etc. Then you just have before and after.
The scene completely is something that has a massive effect on storage. I worked on a police detention centre project and the flooring was hardened resin, which had different flecks in it. So the camera saw a constantly changing image even with an empty cell! At night with the ir on it was even worse.
Its a complete lottery at times, we had cameras at 6Mbps and the image was average, but that was more the camera. They only had 86 cameras and set to 1Mbps 96TB wasn't enough. Turns out windows, which the vms was working on needs 40Gbs per camera