Is It Possible for a 4 Channel CCTV System to Serve Adequately in a Small Business?

In my research on small business camera systems, the term “4 channel CCTV system” keeps popping up as a useful solution for small businesses with very few areas that require monitoring. I am considering installing four cameras at the entry point, sales area, back office, and the loading bay. Would a 4 camera system offer sufficient protection in such a case? One other advantage is that a 4 channel CCTV system could be upgraded in the future if more cameras were needed. For business owners who have already installed a 4 camera surveillance system, would you please share your experience with its performance for day-to-day monitoring?