Depends on how much time and effort I want to put into it. A full OOTK takes a prohibitive amount of time, and is also very heavy introspection. In the past I've done the whole caboodle, an LBRP, invocations (HRU), every operation, EDs, counting, yet another LBRP at the end... everything "by the book. Those experiences were very interesting, but hardly practical, I'm also a working dude who has to sleep and go to the gym sometimes.
So not always. It really depends on my mood. It helps set the atmosphere, especially if you do everything, but even saying just the invocation is cool, too.
There's actually another passage I like to say aloud, on page 218 of the Book of Thoth.
""Aiwaz! confirm my troth with Thee! my will inspire
With secret sperm of subtle, free, creating Fire!
Mould thou my very flesh as Thine, renew my birth In childhood merry as divine, enchanted Earth!
Dissolve my rapture in Thine own, a sacred slaughter
Whereby to capture and atone the Soul of Water!
Fill thou my mind with gleaming Thought intense and rare
To One refined, outflung to Naught, the Word of Air!
Most, bridal bound, my quintessential Form thus freeing
From self, be found one Selfhood blent in Spirit-Being."
I'm sure it has some magickal meaning I'm not aware of, but I like it because it makes me feel the divination is "bigger than myself," so to speak, in service of Will.