If you are looking to add real-time clock (RTC) functionality to your Arduino project without the headache of complex I2C communication, the library is a fantastic, lightweight solution.
The library was originally in the public domain and is now primarily maintained on platforms like GitHub (chrisfryer78/ArduinoRTClibrary) . It is not always available in the built-in Arduino Library Manager, so manual installation via is often required. virtuabotixrtc.h arduino library
The DS1302 module has a small silver coin cell battery slot (usually a CR2032). If your clock is losing time when the Arduino is unplugged, check or replace this battery. If you are looking to add real-time clock