FROM PERSONAL EXPERIENCES:
As a Jr SQL dev, I've have always tried to abide by one rule: there is a median between Work and Home, and I will always stay in it. So far, for the last 3 years, this has been true (I have a 2 yr old, greatest part of life).
When 5pm hits, its home time. But, from 8am-5pm, its SQL, all day, everyday.
Even when surfing SQLServerCentral & SQL blogging, it should be a part of your breaks, lunch, and maybe 30 mins to 60 mins of work time, not home time. I know not all businesses/managers see it this way, but my experience so far with various ones, allows for these type of learning situations.
I think when it comes to us SQL folks, we get split into two groups: Technical and Analysts
The technical guys I see are usually those that can answer any question SQL server related, but are also the guys that work the longest, and have turned this into their hobby and home time.
The analysts guys I see typically have been those who know the technical portion of their job well enough, but also grasp other portions of the business, with much thinking towards other technologies and methodologies. These guys, for what it is, make greater use of their 8-5 (because they have too with their brain-gerbils running at full speed), leaving at 5 to join the family and enjoy life. I've met more managers looking for the family guy and team player who knows enough, then the nutzoid SQL-geek.
Its all in what you want out of life, but I must say to the other young junior devs out there: If you want to enjoy life with family and friends, avoid getting into the habit of being SQL obsessed 24/7 now. Maximize your 8-5, because when you hit 35 and your kid is 7 and you dont remember much from 1-6, you can't get that time back.
Again, all of this is from personal experiences. I understand everyone is different.