We don't have TVs or phones in bedrooms and that goes for DH and I too, the children (eldest 14) understand that it's bad for sleep quality and quantity and are scathing about their peers who send messages in the early hours.
However the over 11s have free use of their phones from 8am til 8pm, and 9pm in the holidays.
The secondary age DC have gaming PCs in their bedrooms but with remotely controlled access times (DH is a programmer) and they can't use them after 8pm.
We are all up by 6am in term time so even the 14 year old is upstairs for 8:30pm, DH and I go up at 10pm.
In the long holidays though the younger 2 (9 and 12) both go to bed at 9:30pm - they have a bedtime because they won't lie in long enough to compensate for going to bed any later than 9:30pm. They're asleep by 10pm and not allowed to go downstairs or do anything except go to the toilet and read in bed before 7am. Eldest doesn't have a holiday bedtim because she's the only one who will lie in past 7am in the morning so can still get enough sleep, but she almost always chooses to goes to bed when her younger siblings do and reads.
If we're working the next day we go to bed at 10pm so don't really get adult only time, though TV is adult choice (family friendly but not kids choice) after 7pm. We watch things not suitable for smaller children with the 14 year old if she chooses to stay up after 9:30pm (15 rating type stuff, not 18) but have only been doing so this holiday, didn't before that.
There are totally unsuitable things we like to watch but have to save for non work nights when DH and I can stay up past 10pm because we can lie in past 6am the next day!
You do have to adjust slowly, you can't reasonably send a 17 year old to bed at 9pm when they have the following day off, and that age will roll around very soon...
An alternative of course is to have a TV in your own adult bedroom, but we're resisting anyone having TVs in bedrooms - much less hypocritical to have the same rule for everyone IMO and having a TV in our room would set a poor example of good sleep hygiene.