The gushing viewers

The first viewers were apparently gushing ‘What a lovely property! Fantastic features’. We know from the house buying secret code [We seek it here we seek it there] that this means they think it’s great, but not for them.That's ok as another viewing is booked for Wednesday and another on Saturday.I’ve heard that it takes 12 viewings to sell a new house. How many to sell a ‘previously owned’ house?