Sorry, this is probably a dumb question but I'm brand new to cake decorating and getting ready to purchase some pans for my classes. So I am wondering what is the reason you would use a 3 inch pan as opposed to a 2 inch? Is it just personal preference or are they used for specific things?
Most of it's personal preference.
I prefer 3 inch pans because I'd rather back fewer, taller cakes and torte them a couple times. They work better with some of my personal preferences for design (I tend to do smaller diameter - taller cakes than standard).
I personally like 2" high pans ( I prefer Magic Line, which are a true 2" as opposed to Wilton). I had 3" pans at one time and sold them on Ebay, take take forever to bake!!