The other thing to consider is that "2 years" is likely to turn into more. Unless you have a signed contract that states you are being moved back in 2 years, chances are you will be staying longer than that.
Just my opinion after living with many many expats over here. We are all on the "2 year" plan.
Yes, we're currently on the third year of our 2 year plan, with at least one more to go (I hope!).
The first year is always tough emotionally and financially draining (even with a lucrative expat package, there will always be unforeseen expenses). However, after that first year, life becomes much easier, and depending on your package, quite financially rewarding

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Living in a country very different from your own is ofter easier to adjust to than moving across your own country. There will be expat groups to help your transition. You will find that you will make friends with people from all over the world, many of whom you might not have back in your home country, but you'll be glad that you did.
The international schools will be full of other children experiencing the same adjustments and challenges as your own kids. They will learn to adapt and have an appreciation for other cultures. I highly recommend the book "Third Culture Kids", if you are interested in the positives and negatives of international moves with children.
Finally, you will likely find time to be good to yourself. I've lost 20 lbs after finally making time to work out; I'm in the best shape I've been since I was a teenager. Many of my friends take classes in Spanish, photography, cooking, etc. You can have the chance to explore what YOU want to do. Many trailing spouses also get part-time jobs (I tutor math), so it's possible to keep up your skills in your profession.
After two years, I have NO regrets moving to Chile. I wouldn't have said that six months in, though...the adjustment was tough. But definitely, definitely worth it.
