Fuel injector wear compensation methodologies for use with internal combustion engines that alter the injection schedule over the life of the fuel injector(s) by using methods that conduct a primary injection of fuel in the engine (primary fuel event), per an injection schedule within an engine cycle; compare a measured engine parameter(s) to a reference value(s); and then alter the injection schedule applied to the engine, based on the comparing. Another method comprises: during injection events, inject a first fuel in a combustion chamber of the engine; measure an engine parameter(s) of the engine during operation; compare the engine parameter(s) to a reference value(s); add a post injection event of a second fuel during the injection events, based on the comparison. The methods can be applied with single or dual fuels.