Protecting electronic components

I recently received my arduino and mm boards, and I am starting to do the first tests and plan how I will setup everything. Since in my country these electronic components aren't cheap (even when they only sell clones), I want to take all take the necessary measures to protect the boards, motors and any other component. So I am creating this thread (besides for getting some coins because I will soon need the plugins ), to share some ideas and thoughts I have, I hope some of the more experienced users can share theirs, and maybe answer some of my questions or correct my mistakes.

I am planning a 2DoF sim, using arduino + monster moto with wiper motors (I don't have the motors yet so I can't tell much about their specs) and potentiometers for motor feedback. I will use @RacingMat code, and a car battery to power the motors (I may add a battery charger connected while the sim is running but I have to research more about the effects that could have, so not sure about that yet). USB would power arduino and mm boards.

This is how my wiring would look, I haven't fully tested it with motors connected but from reading the arduino code and boards documentation it seems it should work fine:

Here are some of the things I thought I could do to protect the boards:

• Add a fuse between car battery + terminal and mm board (How many amps should this fuse be? equal to the amps both motors can pull at max load or a few less? Any other places where it would be a good idea to add a fuse?)
• Isolate motors from ground.
• Use plastic or any non conductive material to mount potentiometers to the motors (even with the motors being ground isolated, it seems a good idea to not let them touch each other since they are both made of metal and one is working at a higher current).
• Power monster moto board with a different PSU so it wont share those connections with the arduino, and use an opto isolator circuit on all the connections between arduino and the monster moto.
• Make sure to keep everything cool to prevent failures by overheating.
• Prevent inductive kickback, even when the driver may have flyback diodes included, I don't trust it. (I am not sure how to do this, is there a simple circtuit using diodes and transistors one could add between the motors and the board as an extra protection?)

short said: I am running the MMs since XX months under very heavy load and peaks (750W winches), they do the job. They are protected, if one MM is faulty it is at the very first test, meaning they work or they do not work. And if they work and you have cooled them and there is no short circuit and all wires are perfectly soldered - they will do the job as long as you are driving. Plug in and forget it...