And frontwoman Amy Lee says it could have been even longer – as she wasn't sure she even wanted to stay with the band.
The US rockers' first two albums were hugely successful but numerous band members have departed – and Amy felt she needed to start afresh mentally before carrying on.
"The biggest obstacle to making a new record, for me, was trying to decide what to do next with my life," she says, ahead of an O2 Academy show next Tuesday night.
"I felt that for a long time, I didn't know whether this was me any more. I was thinking it was time to do something different now, as opposed to making another Evanescence record.
"I was struggling with that, because for a while I OD'd on it, and felt that I needed to express myself in a different way drastically. I did a lot of experimentation, and wrote a lot of songs that were different."
Things changed, however, and she ended up putting her energies into a new Evanescence album after all. Self-titled, the record features several of the new ideas and instruments that Amy was working on and learning, including more piano and even a harp.
And Amy believes that she has now realised how much Evanescence means to her.
"Some of these songs have been on a really long journey, and gone through a lot of different phases," she says.
I think that I was in limbo for a while, as I wasn't sure what to do.
"I wasn't fully focused on just this record, so I'd say that was the biggest obstacle, trying to find a vision of what I wanted this record to be – I overcame the obstacle, but had a war within myself."
There were other difficulties over the years away, including the band scrapping work with famed producer Steve Lillywhite after album sessions didn't work out.
There have been problems within the group, too, dating all the way back to co-founder Ben Moody departing after smash-hit debut album Fallen in 2003.
That's led to criticism that the outfit are purely a backing band for Amy, but she stresses that the new album is a group effort more than ever before.
"The band is really tight, and this is the strongest live line-up we've had," she says.
"In general, when we play together, something happens and everyone brings something great to the table. So taking that, and working creatively, whether that's rhythmic or melodic or whatever, it was a great collaborative process and you can hear that on the record."
Yet the decision to involve the whole band creatively meant Amy had to undergo a slight attitude adjustment.
"Writing has always been really intimate for me, especially the lyrics, which I still do by myself," she explains.
"After everyone has left I go to my room and write there. But the music itself, I've always been happy working with one collaborator, or two.
"This time we had four guys to work with instead of two, and everyone brought awesome stuff to the table.
"It takes a little bit of trust for me, because this is my baby – this is what I dreamed up when I was 14 and it matters a lot to me.
"But I do trust the guys and I'm glad I took the chance of trusting them, because I think it led to a stronger record."
Now, the band are hitting the road again, with Tuesday's Academy gig already sold out. But Amy admits she still fancies doing something different down the line if she could – including teaming up with a certain French duo-
"What I'd really like to do, if it was a collaboration, would be something really different, like with Daft Punk," she says.
"That would be really cool. I'd be open to most things, I wanna get out there and tour and play our music, but at the same time we have a month in December where we are not doing much so I wonder if there's something different I could do-"
l Evanescence, O2 Academy, Tuesday, sold out, 7pm.