Using Timestamps

Router(config)#service timestamps	Adds a timestamp to all system logging messages
Router(config)#service timestamps debug	Adds a timestamp to all debugging messages
Router(config)#service timestamps debug uptime	Adds a timestamp along with total uptime of router to all debugging messages
Router(config)#service timestamps debug datetime localtime	Adds a timestamp displaying local time and date to all debugging messages
Router(config)#no service timestamps	Disables all timestamps

Tip:

Make sure you have the date and time set with the clock command at privileged mode so that the timestamps are more meaningful.