First of all, no, you do not need a reason to reread the Harry Potter [1] series. However, if you'd like a reason other than "because I love it so much it hurts," then these are extra justifications for plowing through the seven books [2]. Again. Do they get old after the 27th read? I can tell you from personal experience that no, they do not. Here's more fuel for your (Goblet of) fire.
So you can feel like a kid again.
And embrace the nostalgia of reading the books for the very first time.
Because someone asked you an HP-related question and you didn't know the answer.
Unacceptable.
To pick up on little details you never noticed before.
Like this J.K. Rowling-approved theory about Dumbledore and Death [3].
Or to remember amazing things you totally forgot about.
Like how the beautiful relationship between Harry and Dumbledore comes full circle at the end of Half-Blood Prince [4].
Because you miss your favorite characters.
And you just want to hang out with them again.
Because you're in the mood for a guaranteed good read.
Other books just don't measure up sometimes.
Because you're sad and you want to feel happy.
Or because you're happy and you want to feel even happier.
So you can compare all of the books with all of the movies.
And get really mad at all the details the movies left out or the glaring differences between the two.
Because it's a day that ends in "y."
This is a valid reason.
To inspire your Harry Potter travel bucket list.
Because you're stressed.
Keep calm and read more Harry Potter [5].
Because the books teach you about friendship, bravery, and love.
And the lessons age with you. You'll gain even more from the books as you gain more experience with each passing year.
Because you just got a new edition of the series.
Gotta break them in.
So you can escape.
Because letting your imagination run wild now and then is good for you.
So you can read it out loud and pass it all along to younger generations.
Mischief managed.
Because you're going on a long vacation and want to get away from your family.
Byeee.
Because you need something comforting to read.
Bad day? There's a cure for that.
Because you're about to visit the Wizarding World of Harry Potter and you're so excited you can't stand it.
It's the best way to tide you over until your trip.
Because sometimes you just need a little magic in your life.
And you know just the place to find it.
Because you've introduced the books to someone else and it made you want to read the series along with them.
Even though it's SO hard not to tell them what's going to happen.
Because Hogwarts is your home, and you feel like going there.
Always.
And because Harry Potter never, ever gets old.
And you never will be too old for Harry Potter [6].