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i have no idea who's telling you to get the 24". When moving in/out you'll be thankful for having the 20" its big and heavy and takes up space also the desks in the dorms (at least in my school) aren't the biggest...

The handle of the many users recommending a 24" are to the left of the post, FYI.

20" - Superior on the day you move in and the day you move out.
24" - Superior on all the days in between.

It's up to the user to determine which days are more important!
 
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