Reading a Book Series

Series I've started:

Poldark series by Winston Graham
Morganville Series by Rachel Caine
Sookie Sackhouse Series True Blood) By Charlaine Harris
A Song of Ice and Fire (Game of Thrones) by George R.R. Martin
Anita Blake Vampire Hunter series by Laurel K. Hamilton

When I first started reading Anita Blake and Sookie Sackhouse books I picked up whatever book was in my local library at the time. This was years ago and the problem then was that I never read any of the books in order. So I had to start again. 

I bought the Sookie Sackhouse books when they were all £1 on sale but I've only read a few. I read the Anita Blake series and then stopped, I love the character though and the books are full of action. I recently started reading the Morganville series again and I'm on Ghost Town now

I stopped reading both Poldark and A Song of Ice and Fire one after the other as I didn't wantreading the books to spoil the series. That's fine for the Poldark series, I've been reading about one a year but A Song of Ice and Fire I can't remember when I last read it and I may have forgotten what happened.

The problem with me reading a series

• I forget what book I'm on (with the exception of Poldark because I'm reading it often)
• I can never decide whether to read them one after another or take a break
• I take too long to read the next book as I have so many books and then find out Anita Blake is on book 25 and I'm probably on 3 or 4
• I have forgotten things that have happened, including how Anita and Richard met in the Anita Blake series
• I will put it off  because I don't fancy reading about vampires or a big fantasy book and then I realise it's years later and as soon as I start reading them I'm hooked and want to read them all.

I don't think I've ever finished a book series. A future book challenge maybe to read so many books in each series or finish one! 

Do you have a system when reading a series of books. Do you read one after the one or take a break? Or is this problem only for people like me who have no willpower and can't stop finding and buy more books when I have so many already to read?