Fire, disease and debt are never to be neglected. If we take loan from somewhere and neglect gradually it’s interest, compound interest will become so big one day that it will be unmanageable by us. Similarly fire is in form of a spark neglected, gradually it may increase to a blazing fire. Even disease neglected in starting stage with little pain may increase to chronic disease like tuberculosis etc. Therefore it is said: Never neglect these things: fire, disease and debt either smaller or higher are always dangerous.
Ref >> Srila Prabhupada Vani.