There has been much research conducted on the recommended withdrawal rate from a nest egg once in retirement.  Most research points to a maximum acceptable annual withdrawal level of between 4%-5% of net financial assets (excluding primary residence). 

For Americans abroad, investing can be especially complicated. In addition to the usual asset-allocation calculus, expatriate Americans must consider the consequences of two tax systems each of them likely to apply different rules to earned and investment income, capital gains and pension savings - and two currencies, the dollar and whatever they pay their bills in at the moment.