The Eternity Granny

I think I started this giant crochet granny squate blanket somewhere around 18 months ago. Using leftover yarn from various projects (all machine washable, and that's about the only thing the different yarn has in common) and crochet needle number 2,5-3-3,5 or something like that. 

I am not done - far from it - but after a looooong break, I've started working on it again, and I'm really enjoying it. I wonder when it will be finished.. And how big it will be..?