thanks cycco

and then we get into just what one person thinks is "pumping"
what I do is brake strongly, and then the bike go a bit before braking again-- and this is the part that is variable-- how long and hard I brake for, and how long between braking applications (5 seconds, 10 seconds?) completely depends on the hill, the road surface and all the other variables going on (line of sight, traffic volume, road space available, side roads etc etc etc)

"letting the bike go" and at what speeds is again totally dependant on the individual and their take on things, what they think is dangerous or comfortable.
I totally trust my judgement on this and ride within myself and my bikes ability to slow down appropriately for the given conditions and situation.

again, also from all my motorcycle experience, I know that the front brake does a lot of the stopping, so I am not shy of braking hard with the front.
Most bicycle riders I know are afraid of doing this, they think they will flip over, or lock the front, or whatever, and so do the whole "drag the hell" outta the rear brake.

On the racetrack, I have experienced fading brakes (boiling brake fluid) and on touring bikes have incorrectly braked (dragging brakes for too long) and started melting rim brake pads, with scary reduction of braking ability (in my case, in the Pyrenees mountains 35 odd years ago)
You can feel how hand pressure has to increase to slow down when you start to overheat rims, pads -- or disks for that matter, so if attentive , you make the good judgement and back off a bit, or slow down or stop and lets things cool a bit, its not that complicated.

Any braking system does not suddenly get worse out of the blue, you can feel it coming on, and adjust accordingly.