Alarms are often overlooked in favour of CCTV systems. However a CCTV system on its own will only show you what happened long after your property has been lost. With an alarm system you get the opportunity to take action as the crime is happening (investigate yourself or call the police) whilst the bells will hopefully scare the criminals away. The ultimate is to combine a decent alarm system with ANY sort of CCTV system that you can watch in real time so you will be able to tell if the activity shown is criminal or not.