If you're thinking pharmacy, I suggest spending your time wisely and plan on studying for the PCAT. Studying for the DAT as "practice" for the PCAT well be of no use. In fact, the PCAT hardly tests organic chemistry, the bulk of the PCAT is general chemistry 1 and 2. Ochem is 1/3 of the natural sciences in the DAT along with biology 1/2 and general chemistry 1/2. PCAT has calc 1, the DAT does not test past trigonometry, nor will it test physics. The DAT has a perceptual ability test, PCAT does not, you get the point... You'll be studying a lot of unneeded material. Unless you're aiming for those highly coveted DDS/PharmD joint-degree programs, do what have you.