Using those "cube" Bosch relays is a good idea, or alternately, (for water
pressure,) a Square D/Furnas external switch makes a good choice also, with the added benefit of user adjustable cut-in/cut-out settings.
My Furnas switch just failed a few months ago after 28 years of 24/7/365 use.
It would actually still work
if I gave it a rap but went ahead and replaced it.
The motors on the popular pumps, Jabsco/Shurflo/Flojet, are basically just an automotive windshield wiper motor.
My water pump is original to the boat
, it's a US made Flojet, ~3.5gal a minute, needed a diaphragm/valve kit at ~25 years, fixed it, still runs great, motor is quiet.
Ran a few #s for fun, almost rocket science math.
Here in the PNW
, for a person doing an hour or so of commuting each day for work
and some driving on the weekend, it could be more-or-less normal for ~4 months a year to be using the wipers, say ~3>4 hours a week, (could easily be a lot more).
For a 10-year-old car that works out to be ~480>640 hrs. of motor run, (again, could be much more).
On my boat
I use ~3gal. per day of water, the Flojet pump runs a total of ~1 min. per day. After 28 years that's ~170hrs run time.
Many vehicles up here are likely to have windshield wiper motors than probably have well over a thousand hours of run time.
My pump is at 28 years, even at the outside that's only maybe 200hrs time.
When's the last time your windshield wiper motor had a dragging armature, bad brushes, or bad bearings.
I would posit that most people have never had a wiper motor fail in a vehicle.
can break down, the switches ALWAYS fail, the basic motors, not so much.
All bets are off if your water pump is in a wet/salty bilge