One of the most significant advantages of TACACS over RADIUS is the ability to do accounting, hence logging every activity and configuration change on the device.
For those who doesn’t have TACACS server (such Cisco ACS or ISE) you can use the following archive command, on Cisco devices, and even send it to syslog server for long term archive:
logging size 500
notify syslog contenttype plaintext
This will allow you to track, who and what, changes your Cisco configurations J