for me it isn't really about the money.  it's more about the freedom (i know laugh it up) i have working in china.  where, in California, can i find a job that can afford me so much free time and allows me to live as comfortably as i am now?  i lived and worked in L.A. for many many years.  the city is very expensive, and i was working around 48 hours a week at my job.  most of my income was put towards living expenses and my disposable income slowly, but surely, became my "savings."  for me, it's more of the life style change.

the main factor in getting me to go back would have to be family.  something significant and big would have to rear it's ugly head.

It wasn't about the money for me. I really enjoyed being an English teacher. I also enjoyed traveling, and having a lot more freedom than I do now. I miss China every single day... and I'd go back in a heartbeat if I weren't married with a kid.

For me, "enough" is when all the requirements for emigration are met by wife and myself. I think emigrating takes some preparation, especially for the one who have less exposure to the "outside". It can be passing some qualifications (IELTS, various licences), or accumulating some capital.

Ok, appreciate the answers, but, I work here 60 hours/week, when I'm not traveling for business, and I have a family with a 1y/old daughter, so let's come to the vile money and spit a number....

I'm with Monkey here. When it is acceptably easy to get my wife a residency in my home country. It is not as much about when to leave China as it is about when something else shows up. I would like to stay as long as my wifes grandparents are around. They are very important to her, and for me the nicest people here (at least I think so, there are severe communication issues there  )