Regarding maintenance

Mendel - my OCD showing here. Do you know of an easy way to double check if the fluid has actually been changed, after a service? I realize a lot of what a service writer writes up on a service call often depends on the mechanic that is actually doing the work, but how does one tell?

 

The bleed bolt covers (at each caliper) would look clean, or at least "disturbed". If not touched they'd have an undisturbed patina of grime. The reservoir cap should look cleaner, it's fluid cleaner and the level a little different maybe.

 

Although this was not for the Prius but for our Pathfinder Hybrid, the color of the brake fluid in the reservoir was obviously cleaner after the fluid replacement.

Nissan calls for brake fluid replacement every 2 years. I don't know if many Nissan owners actually follow this service interval, but this is true even for their hybrid models and Leaf. Our Pathfinder is 6 years old, but we bought it used last year. From the service record, I could not tell if the brake fluid was changed every 2 years or not. The color looked dark, so without even checking, I asked to have it replaced last time I had the car in a shop for the state inspection.

 

You're getting screwed

 

Ditto for Mercedes: every 2 years or 20,000 miles, whichever comes first.

I've been told its because the brake fluid is hygroscopic (absorbs water) which lowers the ability to tolerate the high temperatures at the brake assembly, creating bubbles, which make braking spongy and less effective.