Driving young programmers through 12 hour days is just a recipe for burn out and technical debt that you'll have to pay back later. I've definitely been there.
I guess it all comes down to what you consider a good work-life balance. For me being able to work from wherever an Internet connection exists and the ability to make my own hours is it, and yeah sometimes that'll mean a few weeks of 10-12 hour days here and there. For some it means a strict 9-5 with an hour lunch at an office park off a highway, which I don't judge, but for me sounds like a nightmare.
Again, as long as you're keeping up with contemporary development practices and are pushing your knowledge I think you'll be able to choose whatever definition of work-life balance is for you and be fine.