The card does not speak of preventive use: the cream is described as a product against dry corns and calluses and is applied locally to the area of the corn or callus. Use on heel skin where there are no formations yet, and a regimen for prevention, are not named on the card.
General information (not a manufacturer's instruction): salicylic acid exfoliates the skin and can irritate healthy skin, so it is better not to apply the cream to skin without corns, and in case of doubt to consult a doctor or a podiatrist.