One of my lever harps got natural gut strings which I am currently not playing (carpal tunnel syndrome, sigh), it's parked in the living room. However, sometimes any gut string will just break at any moment, perhaps once a month usually in the upper 2 octaves (1st and 2nd octave).
The tension is pretty hard but not as hard as a pedal harp. I heard about the breaking point of strings, and that the harp tension is usually around 50%-60% of the breaking point.
Another fact is air humidity by around 40%, pretty constant. Temperature between 19-23 Celsius (66-74 Fahrenheit).
So the question is, why do they break? How can I avoid that? Should I park an instrument by lowering the tension, but what about changes of tension for soundboard and neck?