A system includes an acquisition unit which acquires information indicating working history of each of a plurality of fuel cells; an estimation unit which estimates deterioration degrees of a plurality of members of the plurality of fuel cells based on the working history; and a recommendation unit which recommends that which other fuel cell should replace a first fuel cell of the plurality of fuel cells, based on the deterioration degrees. The method includes acquiring information indicating working history of each of a plurality of fuel cells; estimating deterioration degrees of a plurality of members of the plurality of fuel cells based on the working history; and recommending that which other fuel cell should replace a first fuel cell of the plurality of fuel cells, based on the deterioration degrees.