Just one quick Halacha in the laws of Netilat Yadayim (washing hands). There’s an interesting Halacha case written in Shulchan Aruch in seman 4, Halacha 14. Maran writes [listen to the audio clip for the exact quote] that if a person gets up before dawn, and he makes Netilat Yadayim, (and he can make it with a Beracha), so there is a Safek (doubt) that once Amud Hashachar passes, there is a Machloket (argument) if he should have to wash his hands again to get rid of the bad spirits.
There is doubt and discussion because there is a question as to when does the bad spirit comes? Some say that it comes at dawn, and therefore Maran writes that you should again wash your hands but without a Beracha.
So that would be a case for example in the time of Selichot. At that time, we get up early before dawn, and we make Netilat Yadayim at home with a Beracha, and then we are up fro the rest of the day. So according to Maran, one should try to make Netilat Yadayim again after Alot Hashachar. That could be also in the winter months where a person gets up for class that is real early. You might get up at 5:30 in the morning which could be before Alot Hashachar which could be for example at 6:20. Therefore you make the Netilat Yadayim at home with a Beracha, and now you pray Shacharit at 7:00 or whatever time you are praying after Alot Hashachar. So the proper procedure here would be to make Netilat Yadayim again after Alot Hashachar without a Beracha.