Let me be crystal clear here-- my DD13 definitely "prepped" for the SAT. But it was nothing like what I know some of her peers (and their parents) have embarked upon, even so.
She took about 8 practice tests, and curled up with a couple of different practice books, studied how to write essays, etc. I have no problem with this. It was a total of maybe 35 hours, spread over a couple of months. And yes, when you add that up, figure in ~3hr for each practice test. It was a few Saturday + Sunday mornings.
On the other hand, she was taking it as a high school junior. NOT as a 7th grader participating in a talent search. If she had asked for a prep book as a 7th grader, I'd have given her one. But I wouldn't have gone through her practice tests and looked for patterns in what she was missing, etc...
