THE TIME TURNER IS A PART OF THE BIG PLAN!

(This theory gels in with some of the stuff in SCB: Percy had a Time-Turner. So this is going to be slightly lengthy. Stay with me)

Because, when it came to protecting Harry, the Time Turner was Dumbledore’s safety net!

When Sirius broke out of Azkaban, Dumbledore would’ve guessed he would try to break into Hogwarts, even more so because Sirius kept saying, “he’s at Hogwarts!”, in his cell. Sirius was extremely talented (since childhood) and having broken OUT of a Dementor-protected prison, Dumbledore would’ve gathered that he could also break IN to a dementor-protected school and possibly break through other any extra defences put up at Hogwarts. Dumbledore NEEDED to PROTECT Harry at all costs. And this is where the TIME TURNER comes in. The Time Turner is potentially a means for Dumbledore to go back in time and save Harry, should Sirius manage to (or it would seem so in the beginning) kill Harry.

Here are the supporting arguments:

1. Why did Hermione, alone, get the Time Turner, whereas Bill, Percy and Barty Crouch Jr did not? They had at least the same number of OWLs as Hermione.
   ANS: Hermione was only an EXCUSE to get the time turner. She did not NEED the time turner, just as Bill, Percy and Barty did not NEED it. This is what probably happened: Dumbledore knew that Sirius could potentially break in. Dumbledore was not ignorant and would have considered the possibility of Sirius knowing some of Hogwarts’ secrets, that he himself did not know of, to get to Harry. Dumbledore needed something as close to “fool-proof” as possible - The Time Turner. BUT a device so magically powerful IS NOT so easy to get access of! And why should the Ministry lend it for Hermione’s use whey they would know that brilliant students in the past have managed to do so without it. This is where Dumbledore plays some cards- He uses all his influence in the Ministry to convince them to lend it for Hermione’s use, PURELY FOR ACADEMIC PURPOSES. While the same “Academic” reason could have worked for Bill, Percy and Barty, they simply lacked Dumbledore’s backing. Dumbledore probably argued that Hermione was not only brilliant of mind but has showcased wisdom and responsibility with examples such as going past the Philosopher’s Stone’s defences and figuring out that the creature from the Chambers was a Basilisk. With every last ounce of his influence and logical argument to prove that Hermione stood apart even among the brilliant, Dumbledore managed to convince the Ministry to lend the time turner! The Ministry thought it was for Hermione. It was actually for Dumbledore, himself! Now you could argue that in such a case, Dumbledore could back Percy for getting a time turner for Harry’s first 2 years, (Percy’s 5th and 6th years) again as a safety net. Well, that is my next argument. :)
2. Then WHY NOT use the time turner in the other books/years?
   ANS: We know that at the end of OoP the all time turners are destroyed in the Dept of Mysteries. So time turners can’t be used in the 6th and 7th. For the rest of the years (except the 5th and the 3rd), Harry was in danger only from a “wounded, bodiless” Voldemort. And Dumbledore knew Voldemort, knew his arrogance and weakness. Dumbledore always had an upper hand in the sense that he could predict Voldemort’s action. So, for the years 1,2, (3) and 4, where Harry additionally has his Mother’s protection through her blood, Dumbledore himself was enough to keep Harry safe. In the 5th year, though Voldemort was back in full form, he was acting in secrecy and caution. Voldemort’s target in the 5th year was NOT Harry, but the prophecy. So, all those years are manageable without the time turner. BUT the 3rd year was DIFFERENT. 3rd year, Dumbledore had to protect Harry from a RECKLESS GENIUS, Sirius, who, for all Dumbledore knew, had slaughtered 13 muggles in a swish of his wand. Sirius was NOT bound by any prophecy. Harry’s blood offered NO protection against Sirius. Sirius had NOTHING to lose. It was imperative that Dumbledore had a backup plan. A time turner in such a case would come in handy. (I mean just imagine and replace Buckbeak with Harry ;McNair with Sirius and the Trio with Dumbledore, if you get my gist)