Circuit breakers (CBs) are renowned for their high reliability and long lifespan. As a result, many CBs installed decades ago are now approaching their predefined end of service life. However, this predefined service life does not always reflect the actual condition, as some may still be far from reaching their true end-of-life, depending on their operating conditions and history. To assess their true lifetime, continuous condition monitoring is essential. While previous studies have effectively demonstrated the ability to distinguish between different CB fault types, the evolution of CB degradation remains unclear when faults are artificially introduced. This paper investigates the health condition of two high-voltage CBs continuously through run-to-failure experiments. A comprehensive dataset was collected for all opening and closing operations with various sensors such as vibration, coil current, and travel curve and has been made publicly available for further analysis. Furthermore, features were derived from the sensor data, revealing distinct degradation trajectories over time that can be used to monitor the condition of the CBs. This paper highlights the degradation patterns of these features, some of which are well-suited for continuous condition monitoring due to their gradual changing trend over time that likely correlates with the true degradation condition, while others are less useful as they show abrupt changes only before or at failure. By leveraging these features, we can progress beyond the focus of previous research using only fault diagnosis towards fault prognosis. This shift opens the possibility for accurate prediction of the CB condition over time, enabling more effective maintenance strategies. INDEX TERMS Condition monitoring, high-voltage circuit breaker, run-to-failure experiment, vibration signals.