What spares do you carry in the van when touring?

hitchglitch

Over many years touring, mainly on the continent, we have had various things go wrong with the van.  Once we lost all mains electrical systems for a week and we also have had the fridge fail.  Not practical to hold spares for these situations but what about
water pumps?  Used to carry a spare but now have an internal pump and it isn't practical.

Other things that have failed include the electric toilet flush.

So what do people consider as essential spares?