Palladium and LaNi5-xAlx (x=0.30, 0.75, 0.85), which form reversible hydrides, are used for tritium processing and storage in the Savannah River Site (SRS) tritium facilities. As part of a program to develop technology based on the use of reversible metal hydrides for tritium processing and storage, the effects of aging on the thermodynamic behavior of palladium and LaNi4.25Al0.75 tritides are under investigation. During aging, the 3He tritium decay product remains in the tritide lattice and changes the thermodynamics of the tritium-metal tritide system. Aging effects in 755-day-aged palladium and 1423-day-aged LaNi4.25Al0.75 tritides will be reported. Changes in the thermodynamics were determined by measuring tritium desorption isotherms on aging samples. In palladium, aging decreases the desorption isotherm plateau pressure and changes the a-phase portion of the isotherm. Aging-induced changes in desorption isotherms are more drastic in LaNi4.25Al0.75. Among the changes noted are: (1) decreased isotherm plateau pressure, (2) increased isotherm plateau slope, and (3) appearance of deep-trapped tritium, removable only by exchange with protium or deuterium. Various processes occurring in the tritide lattice which might be responsible for the observed aging effects in palladium and LaNi4.25Al0.75 tritides will be discussed.