When I'm driving around locally, I typically turn the sound off on my Google Maps directions; I know where I'm going, I just want to know how long it will take or whether to use an alternate route. But if I'm going to an unfamiliar location, I turn it on to make sure I don't miss anything.
The other thing I should add is that if I'm listening to music, CarPlay lowers the volume of the music and recites the directions over them. But if, as is more common, I'm listening to podcasts, it pauses the pod, gives the directions, rewinds it back 5-10 seconds, and then starts playing again.
What this all means is that every once in awhile I end up in a doom loop where it is pausing multiple times for directions in rapid succession ("Take this exit. Now get in the right lane. Now turn onto this road for a quarter mile. Now get on the interstate") and I end up listening to the same stretch of the podcast over and over again.
As far as I can tell, the auto-rewind is the default setting and there's no way to change it