I do it in the reverse order.
Flats first.
I don't bother with flat darks but do use bias/offset frames that I take next.
Lights
Darks last.
My reason is that my flats are taken with my observatory closed and a flash reflected off the roof towards a white wall.
I then opent the observatory and take my lights.
The darks are taken when I'm packing up or sometimes left to do by themselves when I'm finished depending on how late it is and how sleepy I am.
