With alarm systems having the sensors facing the doors or windows, possible entry points, it allows for faster activation. Instead of waiting till someone is already inside
Having minimal entry delay also helps to ensure no-one is inside that shouldn't be there. While also ensuring only designated people are.
The same can be done with internal cameras, making sure they cover the desired area + also the nearest potential entry point. This allows earlier detection & response time.
Have systems that alert your mobile or e-mail account directly. Just because you buy a system from a business, doesn't automatically mean they should do the responses. Your system, YOUR CHOICE who responds.
If installing a system yourself or Technically minded, consider getting a CCTV 5 in 1 Camera tester to ensure that your cameras are set perfectly.
Test your system periodically, to ensure that everything is still set the way you prefer, or adjust as necessary.
With camera systems, ensure that the lens or dome is checked & cleaned regularly so you always get the clearest images possible.