I would appreciate if you could please tell me is there a compulsive period that a battery from a fire panel must be changed or does it just depends if fail a voltage charge test.
As we have just changed maintenance company and they have informed me that the batteries has to be changed every year !
I will appreciate if you could verify if this is correct.

Its down to what the manufacturer says in their guidelines. The life expectancy of a sealed lead acid battery varies between 3 and 5 years (Depending on brand) Batteries should be tested at least once a year.  If they fail the test they should be changed, but to fail every year ? A lot of companies use a specialist battery discharge test meter. This meter gives a reading of the "approximate remaining capacity" of the battery under test. You could ask them do they use this meter and if so can you see the results yourself. (It is not uncommon to log the results of each battery test, so that you can see over time (years) the resulting figure getting lower and lower. The battery should be changed before it gets below the limit set for that battery capacity)

Also it is a good idea to write on the battery its installation date with an indelible pen.

 

You are being ripped off. The industry standard for battery replacement is 4 years unless it fails before then (which it shouldn't)