This is always determined in conjunction with you because there may be cost implications. As a rule I will be wherever I need to be to be most effective, always recognising that this may change as assignments progress.
For example, for an assignment based in Hong Kong to recover a large material handling project, the design authority was in Denmark. It made sense to be in Denmark for some days each month but this reduced as the design matured and construction/commissioning accelerated in Hong Kong.
For a technology transfer assignment to set up nacelle and hub production in Central China, it was most appropriate to be based in China (typically on 30 day tours) but to spend some time in Germany at the licencing company.