Over A Decade Of Fanfic And Still Going Strong...I started more than a decade ago when I got bored since I'd finished all my library books. My first fandom was Harry Potter and then it ballooned from there into almost 20+ other fandoms. I find myself reading almost all day despite the fact that I may have essays or exams coming up soon and even when my eyes get tired, I'm like "whatever, just another chapter!".
I found that leechblook (for firefox) really helps. I pretty much blocked all possible fanfic sites (AO3, FFN, etc.) and went cold-turkey. The first few days were rough, but it got better after a week or two. However, I just had a break a few weeks ago and have relapsed back into my fanfic addiction... =(