New Book Series Dilemma

I finished reading a book last night. The next in the series isn’t due until next year.

I am going away for work for a couple of days tomorrow so I will start a new book tonight and take it with me tomorrow to read while away.

Now I have my dilemma.
I have a couple of series of new books. One of the series I read around 15 years ago but have been wanting to read it again. It will be the first out of a series of 4 books.
Or I have a completely new book series, with 6 books (a movie came out in the last 2 years based on one of the books) which I have never read but watched the movie.

Do I start the series I have never read? Or do I play it safe and read the series I have been wanting to revisit for a while?

1st Note: I am not a fast reader. Usually a couple of chapters at night before bed. A book can last me a month, maybe more depending on the length.

2nd Note: Previously read series is “The Hobbit” and “Lord of the Rings”. New book series is the “Dune” series

3rd Note: I like Science Fiction and Fantasy

by BettyGrizedale