I do like tracking my reading in Goodreads having started doing that last year. Though like some others here I am not entirely convinced that participating in numerical based challenges is necessarily a good thing since it is too tempting to put those larger tomes to the side for a little longer.
So far this year I seem to have read 112 books / 36,000+ pages (of the ones that have page counts on their Goodreads edition anyways). I'm not a speed reader by any means, I work full-time and spend far too many hours after work doing calibre plugin development or organising my library, but since getting a Kindle I tend to read a lot more and in more places than I used to.
As for "taking a break" after finishing a book, I find that switching genres is enough for me if I feel a bit jaded, I have so many, many books I want to read I can't wait to dive into another one! Reading a long series back to back can get stale real fast particularly if the author gets repetitive or the books are relying on the fact that they were published a year apart. I just alternate my way through about a dozen different series at the moment (only one book at a time though!) depending on what I feel like, and throw in the odd standalone for variety too.
Someone asked how "accurate" the calibre count pages plugin is - as the author of it the answer is it is about as accurate as anything else is.
The only way people could come up with one page count number for a book is if it was only ever published in one printed format with one font size and one edition. If you lookup a book on goodreads you can see the huge range of the page counts many books have across the printed editions alone - large print, special editions, different publishers, revised editions, etc etc. Word count I find to be a more consistent indicator of relative sizes of books, but that also will get impacted by how much "other stuff" is inside the book, like previews of upcoming releases, and appendices of extras. Anyone who has read a Star Wars novel on their Kindle will know that the book "finishes" at about 70% and the rest is advertising other books in the series