I try to take them two at a time. My ratio to animes I've finished versus animes that got lost in the shuffle is not the best (for example, I'm pretty sure I have to restart watching Nadia, it's been so long) so with a very long series like Monster I try to move with a purpose.
Of course, I have at least ten months of backlog on DC and Marvel I am still moving through at a snail's pace when I could be through by just sitting down one day and reading a bunch in a block, sooo...