No, there is nothing in the rulese stopping a player from being deadly boring and saying "I roll Scholarship to find a book that, uh, helps me prepare. Success, cool. Ok, I roll Scholarship again to find another book that, um, helps me prepare."
Nothing that is, except you, the GM. Stopping your players from being deadly dull and dragging down the game is one of your important jobs in Fate games. You can do that by skipping boring things, or by redirecting your players away from boring choices toward interesting choices.
In this specific example, there are two reasonable responses. One is:
Okay, whatever, that sounds boring and we know you have plenty of time to prepare, so let's just assume you do some research and go shopping at Walmart for useful things and let's skip to the spell.
The second reasonable response is:
That's great and all, but actually I'm going to treat your first roll as "research in the library". So yay, you've found all the books that are useful for this ritual! Now do something different. Aren't there some spirits you can summon to ask for information? You just made "friends" with the spirit of Jack the Ripper, didn't you? Don't you want to ask him how to use the blood that you gathered from the scene of the crime? Doncha? Huh, doncha? Oh c'mon, it'll be fun.
Usually, boring Thaumaturgy preparation is just a failure of imagination. Imagination is what roleplaying is about, so don't let your players skip it if it's an important casting. But roleplaying is all about imagination, and that's a muscle that can get tired. To supplement your group's imagination, Rick Neal has worked up an excellent supplement to his main Thaumaturgy article with a followup Thaumaturgy prep "cheat sheet" article that takes every single DFRPG skill and suggests a "make a declaration" use in Thaumaturgical preparation. It's good for getting the creative juices flowing, and pulling in those actions (and skills) that might otherwise be overlooked. And they can lead to interesting situations meanwhile, as failures complicate the situation.