Generally, we turn off the runway when it's safe to do so, as opposed to being told to exit at a certain point. Not uncommonly, when air traffic control does request that we exit at a certain point, we will advise them which one will be using...it may not be (and often isn't) the one that ATC advised we should use.
A large airplane such as the B747 takes a lot of runway when heavy. Think about it this way: our center wing fuel tank, if filled, holds more weight than a loaded DC-9...and that's one fuel tank. With a 630,000 lb landing weight, a lot of runway is required, when we're heavy.
Brake energy and the heat we develop during landing dictate which runways we can use and the amount of braking we'll need on the runway. The turnaround time from one landing until the next departure is important to consider, also. Hot brakes can delay turn times. Long taxi times, such as one gets at larger airfields like Amsterdam, can heat tires substantially, as well.
The runway that's to be used, as well as it's relationship to the taxi routing, and taxiway or access occupancy, are important considerations.
We generally roll to the end unless some other extenuating circumstance exists, but we also generally operate close too maximum landing weight, too. Other operators may or may not be the same.
The same may be said for departures. Not all departures begin at the beginning of the runway, but may be planned on intersections, for a variety of reasons. It's up to the crew to determine what they can, or cannot accept.
Many airports use separate runways for departures, and for arrivals. Arrival runways are sometimes shorter than departure runways (departing aircraft are heavier and require longer distances for takeoff). The runway access points may not be the same for both runways, and delays crossing either runway, or routing to the terminal or other destination on the airport, vary, and may vary throughout the day.