I would say it depends on where you go and how you live while you are there. While I was in Japan (high cost of living), I knew people making twice as much as me in USD per month while they were in Korea (paying cheap, cheap, cost of living at the time) and they came home with nothing in their pockets because they blew it all living like kings for a year. I came home with a little nest egg. And I would agree with Regan above. Coming back to Canada with money wasn't the point of going, it was just a nice added benefit that happened to come up because I lived intentionally while abroad.
Usually, a maximum 70% of your salary is convertible to your home country's monetary unit. Some countries may allow less and some allow more. Depending on your lifestyle, you may have savings or you may return home to start from "A". Gaining experience and travel opportunity is a good incentive enough. However, because most ESL teachers are from the West with Western lifestyle (of course), then hmmm...
As an experienced teacher I could easily send $1000-$1500 home every month and have more than enough to also support my wife and daughter here in China. (Very low cost of living)
However, once you start finding the hidden job markets, then that becomes a moot point. My current opportunity is going to make me more money in 1 year than I made my last 10 years in Canada...... Seriously.
BUT!!! I am no longer just a teacher! It took me 8 years to get here, but now that I can speak Chinese and made some contacts...... WheeeeeHaw! Look out Lexus SUV!!! Here I come!
i could send upto $1500 a month home from my $2000 salary after local tax deductions as cost of living is low even in korea, but what will drain your cash is if you start travelling in asia and doing trips back home.
I spent $6000 during my aug/sept vacations for two trips to china and a trip back home. In winter break I went to japan and back home again so that all keeps draining cash
luckily i cashed in my airmiles to pay for two winter 2012 trips in asia so it balances out!!