Depends on the series, and my mood while reading them.
For example, tried to binge Stross's
The Laundry Files series earlier this year, in preparation for the latest in the series. Got about three-quarters of the way through before I kinda of petered out - taken all at once like that, the increasing grimness of the storyline was getting to me, and I had to set them aside for a bit.
On the other hand, picked up
Rivers of London and enjoyed it so much I'd bought the next six books in the series almost before I'd finished it, and proceeded to binge them in about two weeks or so.