That depends a lot upon the amount and kind of flying that you do in the aircraft.
If, for example you fly 600 hrs a year on the North sea and get a good workout twice a year for your OPC's in the aircraft then your requirement for Sim' time might be less than for a corporate guy who does 150 hrs a year and who's access to the aircraft for training is limited.
In my experience, the normal annual recurrent courses offered by sim providers range from anywhere between 4hrs and 10 hrs per pilot.
Geoffersincornwall might be able to offer some better guidance on this.
OH