Hogwarts' Dorms

[Robert Jones]

No: HPFGUIDX 79481

The students keep their same dorm room for all seven years.  I think 
it was in the GOF that Harry says he was glad to see his old room 
again when he arrived September 1.  Each year the new class just 
takes over for the previous seventh years.  I assume the rooms can 
be adjusted the size of the room each year to accommodate the number 
of students in that class since the Room of Requirement can change 
its size, Arthur Weasley could make his Ford Anglia bigger inside to 
hold more than it looked outside, and the tents at the World Cup 
were bigger inside than outside.  

This brings up a previously discussed issue of how many students are 
there at Hogwarts?  I don't think each house has a new class consisting 
of exactly 5 boys and 5 girls each year -- part of the humor in the 
books is JKR using odd numbers where we would expect nice round numbers 
and that would apply here.  (Are there more than 3 Gryffindor girls in 
Harry's class?  Only three are mentioned.) 

Also, if the school had to admit exactly five boys and five girls for 
each class they would have to find them during the admission process 
before the school year began, and so what would the Sorting Hat have to 
do?  The students' houses would already have been determined before they 
got to the Sorting Hat.  Also, it would odd to say "There is a muggle boy 
in Cornwall who would be perfect for Gryffindor, but we have already 
determined our five for this year, so we will have to skip him."

Boris the Bewildered