I have a project that uses several high power DC solenoids (50 VDC) that will have ~10 feet of wire between them and the driver board. This is for pinball machines. These solenoids typically come with flyback diodes pre-installed on their terminals which makes sense and is very common with any switching inductive load.
However, when I look at schematics for the old driver boards from their heyday in the 80's and 90's I see flyback diodes there too.
Is there a reason you would want flyback diodes at both ends of the wire run?
simulate this circuit – Schematic created using CircuitLab