Grizabella
Wow, thanks everyone for your responses!
I've always cut my deck in thirds, but use my right hand (I'm right-handed, so it feels weird using my left...and one should be comfortable during a reading). I always put them together again based upon how the card stacks feel to me intuitively.
So, I guess it is reader's choice. It is interesting how things just become a matter of course.
DarkWolf
That's actually true---the right side of the brain does control the left side of the brain. Interesting point I didn't think of.
As a person learns Tarot they develop their own routines with the cards and I've found that, for me, there are just things I evolved with as routine and now if I omit a step or two, it doesn't quite feel right. I can still read the cards alright if I change some of the routine but being a creature of habit, it just feels a little odd to do it differently.
I've said it before on AT---maybe worded differently---but the "magic" is in you, not in the cards. My cards are a just stack of card stock with art work on them. I'm just an old woman like any other old woman. But when I pick up my cards, we turn into something else. That's where the "magic" happens. I use quotation marks around the word magic because that's just a word that's easy to use to describe it. I don't practice magic or even know anything about the Tarot magic. Just develop whatever feels right for you and don't worry about the "shoulds" and "oughts" you come across in reading about Tarot or learning what others do. None of it matters, really.