On a bad day I roll out of bed at 7:55 for work at 8, don't take a proper lunch hour and find myself exhausted by 3pm so I have a nap.
On a good day I get up at 7, have a couple of brews and wake up a bit, maybe tidy round a bit to get myself moving.
Work (with Pomodoro method, so 25 min on/5 min break - doing little house jobs, a 5 min Youtube video, a quick stretch, a stand in the back garden staring blankly at the sky trying to soak some vitamin D in) from 8 - 12.30.
12.30 - 1.30 I turn my laptop off, and eat lunch, watch an episode of something, read, put some washing in, talk nonsense with DH, whatever.
1.30 - 4 I work, again with Pomodoro timer. And at 4pm, I step away. No ifs or buts.
I manage a team of people and I ensure they also take a full hour for lunch, and finish exactly at 4pm. If something isn't going to be finished that day, we either help each other get it done, or it waits til tomorrow. Nothing we do is so crucial to the world that it requires people to work outside of their paid hours and we expect people to work and live with that in mind - they're much happier for it.
The problem is I can do this because I'm the boss, and my employees can because I tell them to, and because we have a business which doesn't assign more to a particular person's workload than can be done within their working week. If you're working in a business where your workload is too high or your managers expect overtime, you're going to get work creeping into your home life unless you set very firm boundaries and stick to them, sadly.