So the author of our pre-calculus book, and head of the math department wrote a little "How to study math" handout that advises us how much time and energy we should spend studying.
He says that for every "academically rigorous" field of study like math, physics, chemistry, architecture, etc we should spend 2 hours of of time outside of class for every single actual hour spent in class (not credit hour.)
He states that since we spend 8 hours and 40 minutes in our pre-calculus class we should spend 18 hours and 40 minutes out side of class studying and doing homework. Now... I'm not a math teacher but 8 and 40/60 * 2 = 17 hours and 20 minutes when I do the math...
He then states we should be expected to be spending 27 hours and 10 minutes total in class and out on each 4 credit class. (Again.. with the weird math 8h40min + 18h 40min = 27hours 20 minutes...)
He also states that we must get 8 hours of sleep no matter what to function at peak efficiency, otherwise we are wasting ours and the instructors time.
There are a 168 hours in a week.
Using his numbers...
If we get 8 hours sleep every night there are 112 left over.
My summer schedule of 8 credits of math and physics I should be spending 54 hours and 40 minutes a week in class and out of class academically.
Which should leave me 57 hours and 20 minutes a week, or 8 hours a day to work, shower, eat, etc.
But lets say you had my past spring schedule of 12 credits.
Why then, you should be spending 82 hours academically, leaving you with 30 hours a week, or 4 hours and 20 minutes a day to work, shower, eat, etc.
But lets suppose you are an architecture student taking the recommended 16-18 credit load.
At 16 credit it a 109 academic hours, leaving you a glorious 2 hours and 40 minutes a week, or 22 minutes a day.
At 18 credits you should be spending 123 hours, leaving you with an -11 hours with which to do all those distracting non-academic functions.
Even if you do you basic algebra correctly (which some professor are apparently not apt to do) according to his theory you should spend 26 hours total academically for every 4 credit class.
Which means I this summer I should have 52 hours free a week.
Last Spring I should have had 34 hours free a week.
At 16 Credits 8 hours free a week.
At 18 credits -5 hours free a week.