For my 1st go around, I'm glad I planned on multiple days. The sheer amount of items, tables, things to look at, giveaways, etc is overwhelming. It took me all of Wednesday nights preview, all day Thursday and all day Friday to feel I got a good pass at most things. And I'm also sure I didn't get them all.
For example, on the Wednesday night preview I thought I would get a pretty good overview of things. One of the first booths I walked by was .10/.25/.50 cards and they had tons of boxes. I pretty much spent Wednesday night at one booth! So much for getting a full overview on sneak peak night.
I also didn't wait for or stand in line for any autographs or anything like that. So, if looking to get autographs I can see how that would increase time needed as well.
As someone mentioned, I guess also depends on goals for attending, but for me (searching those low cost boxes!) multiple days were needed/beneficial.
Have a great time!
