VARCHAR(255) and VARCHAR(2) take exactly the same amount of space on disk! So the only reason to limit it is if you have a specific need for it to be smaller. Otherwise make them all 255.
Specifically, when doing sorting, larger column do take up more space, so if that hurts performance, then you need to worry about it and make them smaller. But if you only ever select 1 row from that table, then you can just make them all 255 and it won't matter.
See: What are the optimum varchar sizes for MySQL?
