Get your Alarm System Serviced
The importance of getting your alarm system checked over, and serviced by an approved company every year (most insurance companies require evidence that your alarm is maintained by an approved company where discounts may apply for having an alarm system). If you can not afford that then at the very least every 4 years, as by then the systems backup batteries will almost have come to the end of their lifespan. If its been regularly serviced and maintained then your system should give you many trouble free years of service, but I would suggest you still think about getting it fully upgraded every 15 years or so.
Getting your alarm serviced and fully tested on a regular basis is a wise investment for your system, an annually maintained system is proven to be much more reliable than one which isn't, but so many people have an alarm installed and then expect it to run trouble free for the rest of its lifetime, it just doesn't work that way and this catches so many people out.
The average alarm system only takes about an hour to service, the engineer will check the Control Panel, Detector, Siren and Battery Supply Voltages and current drain. Backup batteries (to ensure a minimum 8 hour backup capacity) are recommended to be replaced every 5 years, Monitoring if installed (monitored alarms would normally be serviced every 6 months and Audible every year in accordance with NSI BS EN ISO 9001:2015), clean and walk test all the detectors, Test sirens and speakers, and finally test the alarm system is functioning correctly. You will of course be advised of any faults found, and be given suggestions for remedies or replacement parts as required