A fuel cell assembly (20) has a plurality of characteristics that extend the useful life of the assembly. In one example, flow field layers are non-porous and hydrophobic such that they have an acid absorption rate of less than about 0.10 mg/khr-cm.sup.2. An electrolyte retaining matrix has a reaction rate with phosphoric acid of less than about 0.010 mg/khr-cm.sup.2. Hydrophilic substrates associated with catalyst layers have an initial transferable phosphoric acid content of less than about 25 mg/cm.sup.2. A condensation zone provides an evaporative phosphoric acid loss rate that is less than about 0.17 mg/khr-cm.sup.2.