Had a coolant sensor fail in a Mazda 5 (Maybe 2008 or so.) We were house hunting 8 hours from home (I was taking a new job.) Found the sensor at an AutoZone or a Napa. Can't remember which. They loaned me some tool to do it in the parking lot. It was inserted sideways, and low, so had quite a bit of coolant come out. Replaced it with some Peak global 50/50 they had. My plan was to change out the coolant when I got home, but I never did. No issues. Traded in the car a few years later.
I did once rent a spring compressor tool of death and a special tools brake kit (Needed that square caliper retraction thing-a-ma-bob.)