Liquid-in-glass thermometers are pervasive throughout industry. These thermometers provide a convenient method for measuring temperature over a broad range of applications with reasonable stability and accuracy. However, like all thermometers, liquid-in-glass thermometers are subject to drift as a function of time and maximum temperature of use. This paper describes methods for the validation and recalibration of previously calibrated liquid-in-glass thermometers to maintain the metrological traceability established with the initial calibration. Procedures and examples are given for visually inspecting a thermometer, using an ice point for a single-point recalibration, and determining uncertainties for thermometers with a single-point recalibration. We discuss when a single-point recalibration is acceptable, and when a full recalibration is needed.