I only use cell phone gps. My old Garmin had been retired years ago.
When we start off for the day, I punch in our destination, look at the overall route on the map to make sure it seems reasonable and head out. If Google tells me there is an accident and suggests another route, my co-pilot does some checking on her phone our paper maps before we turn of.
We have several other apps that we use on the road to find overnight stops, check what food is coming up on the next exits, etc. I also use a Bluetooth OBDII adapter and an app to monitor the vials on my truck. The newer versions of Android let me split screens and see truck vials and maps at the same time.
I've been considering getting a 7" tablet to mount up in my truck to be dedicated for maps and truck monitoring.