Do you need brake-fluid replacement?

I splurged on the $13 tester.

Wife has the Prius out of town just now so I can't take a reading but I'll see what it says next week.

 

I've learned that the ethanol in gas is also <> hygroscopic <>( has to look that one up).
There's a pretty simple test tube thingy to measure it too. To see it just put a few ounces of 10% ethanol gas in a glass jar and add a drop of water. You'll see the drop(s) of water at the bottom of the jar. Than if you swirl the jar around the ethanol absorbs the water and clouds up the gasoline. Eventually water separates out again. Good the test with some non ethanol gas too.

Thanks to everyone for sharing their brake fluid adventures, dealer service experiences and testing results.