When the technician does an alarm service for your home or business. They are there to check the wiring is not damaged (ie. Rodents have not chewed the wiring). Furthermore, that the sensors are clean of dust and grime, and that the backup battery is in good condition. One of the best things is to check that the keypad is in good condition and buttons are not sticking.
Also, The time on site will depend on how many sensors you have. The location of them (as this can vary between Residential and Commercial sites) and also if they find anything that needs to be fixed or replace. Contact the wireless alarm service team that can get you booked in asap.