Agree with Pete there absolutely, and there's lots of variables.
Yep, in answer to your original question, are the fans running after every run: NO. But, if I've been stuck in slow traffic, the ambient temp is greater than 25deg C or it's been driven like a VR should, YES, so as Pete says - it's dependant on lots of factors. These cars are old now, and to get one of mine right (with only 62k and dealer history) it took: crack pipe, thermostat housing, thermostat, radiator upper hose, main radiator, both temp switches on the thermostat housing, radiator fan switch - all to original