I sleep in a little room under the eaves and rafters on the third floor. The only toilet has always been on the first floor.
I don't know why the Dutch so like to have only one toilet in a house, but they do. And it's always in a tiny room with a tiny sink that only has cold water.
During the day, it is great to have the toilet on the ground floor. Statistically, most of one's incidences of needing a toilet are going to occur during waking hours.
But my Dutch family also loves beverages - tea, coffee, juice, Rivela, milk, wine, beer, hot chocolate, anything - and my great uncle and aunt constantly offer them to us. I once kept a running beverage log while I was here, just accepting every beverage I was offered, and the number, I believe, ran to 19. (12? 19? I can't really remember. Over 10. But 19 sounds familiar.)
AND, my Dutch relatives have no qualms about coffee at bedtime. Frankly, I have no qualms about coffee at bedtime either, save one: coffee makes me have to pee.
The problem with needing to pee in the middle of the night when your bedroom is on the third floor and the bathroom is on the first floor of a house with steep, curving, narrow staircases, particularly when you are clumsy, is the high likelihood of falling and dying. Or falling and making a clatter that wakes everyone up. Or falling and damaging yourself and lying helplessly at the bottom of the steep, curving, narrow stairs trying to decide whether to wake everyone up to help you stand up.
(None of those things have happened. But I am very, very careful, no matter how sleepy I am when going down the stairs.)
The situation has, in theory, been alleviated by the installation of a new toilet in the sink/bath room on the second floor, except not, because the new toilet requires pulling a string to get the water flowing, and then waiting a while, and then pushing a button that results in flushing plus a horribly loud noise. Oom C. calls it the spaceship toilet, and it does indeed sound like a rocket at liftoff.
To spare the people sleeping on the second floor, I still stumble all the way down two flights of steep, curving, narrow stairs in the middle of the night.
But today I remembered not to drink coffee after dinner. Maybe that will help.