When to use call_log.agi??

Hello everyone!!
I am automatically calling several numbers and playing a message for them, ervything is working. .. but im not sure when to call "call_log.agi" in this procedure:
before the DIAL(Zap... is called, when placing the actual call to the pstn
or
before the Playback(announcement) in the extension that is described in the "remote agent extension" ?
or even both???
Thanks!
I am automatically calling several numbers and playing a message for them, ervything is working. .. but im not sure when to call "call_log.agi" in this procedure:
before the DIAL(Zap... is called, when placing the actual call to the pstn
or
before the Playback(announcement) in the extension that is described in the "remote agent extension" ?
or even both???
Thanks!