I've never asked for much from my employer for work/life balance other than not working a ton outside of normal hours (e.g. I haven't had children or a major family illness). It seems like the company has a pretty decent work/life balance, but I also think a lot of that boils down to company culture and the people in management that foster it. I think it's really fragile. There's nothing set in stone in the company that people will be understanding.