France - to use tolls or not?

[REC]

Best way I think is to check each section of the trip say in 100 mile chunks on the sat nav or online, toll and without toll and see if there is much time difference. I worked on the principle of it it saves an hour over 100 miles definitely take the toll but if it's 20 minutes don't bother.

Pretty much what we do. The only time we did tolls most of the way was during lockdown when we returned via fastest roads with fewest vehicles on them!