I bought the roll of cotton from CVS when I started rebuilding, when the protank 2 first came out, I don't believe it's halfway used yet. LolYou might be the only one I know that actually has more wire than me.
If I'm using the same tank, I change my cotton every 3-5 days or so (at least it seems that way). I have tons of cotton as well.
Cheers,
Steve