I'm going to watch all 3 Lord of the Rings movies in a row in February. Any tips and tricks to survive such a marathon?

My father gifted me a movie experience with all three Lord of the Rings movies (extended versions) in a row (557 minutes in total according to the website of the cinema, so about 9.5 hours, start is at 1PM).

I've never been in a cinema for this long and I expect to be drained afterwards. What can I do to survive? For example: Should I get ear plugs?