1. A method of fabricating a three-dimensional (3D) object using a 3D printing system, wherein the 3D printing system controls one or more parameters of the 3D printing system to fabricate the 3D object, the method comprising: sensing a characteristic of a component of the 3D printing system, wherein the characteristic of the component of the 3D printing system changes over time; and based on sensing a change in the characteristic of the component of the 3D printing system, calibrating a first parameter of the one or more parameters used to fabricate the 3D object, wherein the component of the 3D printing system comprises a nozzle, wherein the nozzle has an opening through which printing material is deposited while fabricating the 3D object, and wherein sensing the characteristic of the component comprises sensing a characteristic of the opening of the nozzle, wherein the characteristic of the opening of the nozzle comprises one or both of (i) a shape of the opening of the nozzle or (ii) a size of the opening of the nozzle.