to turn the bathroom fan off after my shower? DH says

[skrullandcrossbones]

yes, and it should be left on for hours until someone notices half an hour like he does.

What do you do?

If you want it to clear more quickly leave the fan on and the door open a little - helps the flow of air.

Surely if you leave the door open that's ok too.

well, no. because then you get the humidity (and mould) in the other rooms, too.

We leave ours on for half an hour-ish - or like your DH, until someone remembers to turn it off!