System saves user preference
The user, who is an instructor, has the Gradebook page open and is copying and pasting students' mid-term exam grades from her spreadsheet. 
The user would like to see all 43 students in one page, so she clicks on the dropdown "Show x per page".
She figures 50 would be a good size to display all of her students in one page. She selects 50, and the page reloads. 
The next day, a couple of her students requested their marks to be corrected. She logs in to the Sakai site to see the Gradebook again. This time she opens the Gradebook, it remembers her preference from the previous session and displays the entire list of students immediately.