As a general rule for a Western expat coming over I would suggest the following rule of thumb:

1.2 times whatever your salary would be for the same job in your home country. More for Americans because they still pay some tax (or a tax offset program, which is what some American companies offer). Otherwise Uncle Sam will rob you blind in taxes.

Housing. This ranges from a single person to a large family, but I would think 12,000 minimum for a VERY MODEST villa in an OK place. For a two bedroom apartment in a good to very good location, 9,000 would be tough.

A car lease for an mid-size SUV will run about 3,000 a month. If you love your wife and child, do not drive anything smaller than a mid-size SUV. I threw my worry about carbon emissions out the window after driving here for two days. Buying a car is much cheaper, and you can pick-up a decent used mid-size SUV for well under 70,000.

Private medical insurance. You need this, especially with a baby. Period. I am not saying public healthcare is horrible, but it is overstretched here.

Other Western expat benefits typically include school fees for children, and flights home every year.