On Wed, 18 May 2016 22:10:03 +0100, Clive George wrote:

I am delighted to read about absorbing water, creation of steam,
changing the fluid so it is dry, and the actual boiling points. All
relevant and some mentioned in my question/response. But none of them
seem to support the claim I was questioning: that not changing the
brake fluid makes the brake fluid itself more likely to boil.

If you were able to ensure that the brake fluid was unable to absorb any
water then yes, you would not have to change it so often.

However since that's apparently rather hard, you do need to change it,
because it does absorb the water and boils at a lower temperature.

Of course, an even easier option would be to use a non-hygroscopic
fluid...

But, no. It seems that's not an option. The one manufacturer who did have
gone back to DOT.