British Standards (namely BS 8214 and BS 9999) recommend having a fire door maintenance service/inspection every six months, annually for apartment doors, however the best course of action is to have a risk-assessed recommendation which will be tailored specifically to your building or individual apartment requirements. For example, your premises may have a higher footfall than others and may require more frequent inspections. Your Fire Risk Assessor will tell you how often your fire doors should be serviced during your Fire Risk Assessment.
Following the Grenfell Fire in 2017, remediation projects and investigations in both passive and active fire protection are taking place across the UK. The Fire Industry Association noted following one building surveyors findings that there was a distinct lack of maintenance records, missing or incorrect fire escape signage, and even cases where fire doors had been locked or had the intumescent seals painted over, which completely negates their use.
So, without regular inspections, your fire doors could be completely ineffective without your knowledge. Simply having fire doors in place does not mean that they are in good working order like everything, it needs maintaining.