All 6 books, a few times a year? I'm reading through the series for the first time, and while I'm sure a reread goes faster, it still must take quite a few nights. It is really good though, I'm sure I'll want to do it again once I'm finished.
If you read 20 pages a night, you can cover the whole series twice in 250-ish days. Once you've read it a few times, you can get through 20 pages in like 15 minutes.
I read the entire original Dune series a couple of few times a year, always in bed at night - I imagine, much like people read their Bibles.
Having done it so many times, it's become "low impact" reading - appropriate for situations where reading something new is "too much."