ds1 generally goes upstairs to his room at around 8pm, sometimes he's allowed on the PC at that time and goes up later.
Generally he doesn't go to sleep til 10 or later, but I still pack him off upstairs. I often want to watch something that is not appropriate/appealing for him/them, and I want my peace/my space.
If there's something on that he wants to see (rarely), then we record it for us to watch at a more reasonable hour.
Too often late, late evenings at weekends soon slip into late, late evenings during the week. I work in a secondary school and I regularly see children who are far too tired to cope with the rigours of a school day, let alone learn anything.
For us it works very well for the children to go upstairs at an early hour. They then have 'screen-free' time (no computers or TVs upstairs), and it gives them the opportunity to relax, chill and wind-down from the day. They also use that time for reading, which they both do prolifically.