[AndrewJ]

it varies. Ideally, you'd pulse up to the speed limit (or a little above) and glide all the way back down to a near stop. But few of us have the patience for that kind of thing, now do we?

I'd reccomend gliding down to the lowest speed that's comfortable for you, if you're on the highway though, most people try to keep a plus-or-minus 10mph thing going.
For example, pulse up to 55, glide down to 45. Rinse, lather, repeat.