Our granddaughter is almost 8 years old and lives with us as her dad is in the military and her mother gave up parental rights. Our rule for screen time of any kind is a maximum of 2 hours in a day. We monitor what she watches and require that at least 50% consists of educational material. We downloaded filtering software to her tablet so she only has access to certain programs, and she cannot connect to the Internet except when we expressly permit it which is almost never. No screen time is allowed until she has done chores: folded and put away her laundry, picked up her stuff, helped with the dishes, etc. Television is not allowed during meals, or when she is doing chores otherwise she dawdles.
As it turns out, she would much rather help me fix a meal or bake something than watch TV. She's turning out to be a darn good cook who can identify the fresh herbs I grow in my solarium by sight or smell and can tell if the "pot" needs something when we taste test. No amount of screen time can replace that.
Along those same lines: She asked when she could have her own phone. I said, "When you get your driver's license." She asked when she could have a TV in her room. I said, "When you move into your own house and have a job." We don't have a TV in our bedroom, either. These same rules applied to her dad and aunt (our daughter) who both turned out extremely outgoing, intelligent, and self-motivated.