My daughter is 7 years old and will be 8 years old this year. Is it appropriate to sleep with her father every day?

You need to know why she did it. Actually, your daughter doesn't sleep with her mother, and it's rare to sleep with her father. It can be said that the psychological transition in infancy is very healthy and smooth, from Oedipus complex to Oedipus complex.

As for whether it is appropriate or not, I think premature independence can easily lead to children's subjective rebellious tendency in the future. Grasp this degree and don't try to force her to leave her father to sleep. What needs to be done is to make her understand that her father is not an authority, so that she should not have religious feelings for her father (children often have religious mysticism at this time), so that her father is a person in her heart, not a god. This is the first step, and then you need to let her learn to observe the world by herself, instead of letting others tell her what the world is like. This solved her psychological tendency of wanting to sleep with her father.

Of course, it does not rule out that she has a phobia about dark-related things. If she was scared by adults with things related to "darkness" and "night" when she was a child, then she may have psychological fear of darkness (it must be clear that human beings are not afraid of these things by nature, and the only reason for fear is threats and intimidation). I don't know much about fear. Maybe you can consult some responsible psychologists to help her get rid of this phobia.