A method for estimating a remaining life of a transformer, said transformer being monitored by a monitoring device, and said method comprising: receiving data elements collected at said monitoring device that characterize a degradation of insulating material in said transformer during operation of said transformer over a period of time, said data elements being received at a processing system from said monitoring device, and said data elements representing a current amount of dissolved gases in said transformer that correlate with said degradation of said insulating material in said transformer; wherein said dissolved gases include carbon monoxide and carbon dioxide (CO 2) in transformer oil of said transformer, said carbon monoxide and said carbon dioxide evolving in said transformer from said degradation of said insulating material; characterized by: determining an adjustment value (142, 144) for said dissolved gases in response to a through-fault and/or maintenance event (160, 162) occurring at said transformer;wherein said adjustment value is the sum of the amount of carbon monoxide and carbon dioxide removed during a maintenance event, and an amount of dissolved carbon monoxide and carbon dioxide calculated for a through-fault event to represent a reduction in the degree of polymerization of the insulating material; adding said current amount of said dissolved gases with said adjustment value to obtain a total amount of said dissolved gases; estimating a degree of polymerization value using said total amount of said dissolved gases; converting said degree of polymerization value into a measure of said remaining life; and presenting said measure of said remaining life to a user, wherein said determining, adding, estimating, converting, and presenting operations are performed by said processing system. receiving data elements collected at said monitoring device that characterize a degradation of insulating material in said transformer during operation of said transformer over a period of time, said data elements being received at a processing system from said monitoring device, and said data elements representing a current amount of dissolved gases in said transformer that correlate with said degradation of said insulating material in said transformer; wherein said dissolved gases include carbon monoxide and carbon dioxide (CO 2) in transformer oil of said transformer, said carbon monoxide and said carbon dioxide evolving in said transformer from said degradation of said insulating material; determining an adjustment value (142, 144) for said dissolved gases in response to a through-fault and/or maintenance event (160, 162) occurring at said transformer;wherein said adjustment value is the sum of the amount of carbon monoxide and carbon dioxide removed during a maintenance event, and an amount of dissolved carbon monoxide and carbon dioxide calculated for a through-fault event to represent a reduction in the degree of polymerization of the insulating material; adding said current amount of said dissolved gases with said adjustment value to obtain a total amount of said dissolved gases; estimating a degree of polymerization value using said total amount of said dissolved gases; converting said degree of polymerization value into a measure of said remaining life; and presenting said measure of said remaining life to a user, wherein said determining, adding, estimating, converting, and presenting operations are performed by said processing system.