1. A method to learn behavior of maintenance costs of products and determine maintenance costs of products, using a learning database containing product characteristics maintenance agreement conditions and maintenance costs associated therewith, comprising the steps of: selecting at least one product characteristic from said learning database; determining, from said learning database, first maintenance cost estimations associated with modalities of said at least one product characteristic and building a first table storing the modalities and said first maintenance cost estimations associated therewith; selecting at least one maintenance agreement condition of said learning database; and, specifying values of said at least one maintenance agreement condition, determining maintenance cost correction coefficients associated with said specified values and building a second table storing said specified values and said maintenance cost correction coefficients associated therewith; wherein said first and second tables characterize maintenance cost behavior of products contained in said learning database.