Do other things first. Protection issues such as training and establishing prevention strategies must be addressed. There are several less expensive ways of assuring your safety. Video is just one additional tool in the whole spectrum of crime prevention. Don't be lulled into a false sense of security believing that once you've installed equipment to protect your investments your job is done.
Crime prevention requires careful thought and reassessment periodically.
Having actual video footage will reassure the police that a crime did take place. There have been reports of robberies taking place when in actuality the clerk on duty pocketed the cash and reported a robbery to cover the loss. Yes, some people lie. The video will also show what the culprit touched during the crime and this assists investigators in obtaining latent fingerprints. Too often as the sun sets beautifully in the west and beats in your windows, someone walks in and robs your business.