I don't know about other nations, but in the USA you are required to be given the -option- of having 1/2 hour of unpaid break time for any shift exceeding 6 hours. Assuming you actually take that option, and actually eat during that break, then from punch-out you might take a few minutes to arrive at and settle at your break place, 10-15 minutes to eat, 10-15 minutes to study, a few minutes to return to the clock and punch in again. Anything more than that, and you should count yourself lucky.
8 hrs sleep, 8 hrs work, .5 hour unpaid break, .5 hour in, .5 hour out commuting is 17.5 hours. 2.5 hours cooking, hygiene, housekeeping, medical, friends and family, that's 20 hours a day. In your remaining 4 hours, how much will you devote to SRS?
I haven't allowed time, mind you, for a significant-other or a particular hobby other than studying Japanese, or working more than 40 hours which is pretty much required if you are at all career minded, so now '3-4 hours' is a pretty extreme answer in my mind.
If you're career minded and not working the minimum, or you're hourly wage instead of salaried, then you can probably assume you're working 50-60 hours and cut that 'free time' in half. Now 3-4 hours of study per day is insane compared to 2-3 hours of 'free time'.
Of course, if you -are- salaried, you can make some of that up on your day off and/or weekend, if you have one.
Note that in the extreme case, 1/2 hour unpaid break could mean that you get 1/2 hour unpaid break and 23.5 hour workday, 6 days a week. (It is technically illegal to require a 7 day workweek, so you do get a day to recover.) I don't know of any real case of such unrealistically stressful work, but labor laws don't do crap to prevent it.
1/2 hour, unpaid break, once per day (if the day exceeds 6 hours). Period. That's the 'law'. Food, break space, etc., do not need to be provided on site. Add travel time to the nearest fast food joint and you may barely have time to wolf down a burger. If you get the more-or-less standard 2x 15 minute paid breaks and 1/2 hour unpaid lunch break in an 8 hour shift, feel lucky, because that's -not- law, it's just common. Only the 1/2 hour unpaid break is law.
Mind you, I'm perfectly willing to leave my pair of jobs for something better if you think I'm insane and simply being screwed over. Make me an offer. I'm primarily a cook, with excellent skills in English, reasonable skills in web design and computer programming, and considerable culinary skill, not to mention reasonable skills in Japanese and somewhat poor skills with German and Spanish. Ideally, I'd like to run a western-style Bistro in Kyoto if you care to fund it, but Tokyo would be perfectly acceptable.
Edited: 2013-04-09, 3:52 am