So there is a fabulous LDS curriculum that I plan on starting next year for history, see curriculum here, and with this curriculum they recommend rotating subjects. Well, I'm not starting their curriculum yet, and when I do I may only do history, but I'm going to try subject rotation now. I've been noticing Spanish is sort of suffering and science is sporadic SO here's the rotation. Devotional (song, prayer, scriptures in one form or another), pledge, reading, writing and math daily and then one subject per week of science, social studies, and spanish. I should also have listed instruments daily....but we're slacking on the daily-ness ;) of that as well.
Right now we're having a problem with Superman retaining his Spanish. I think that emphasizing Spanish for a full week every three weeks will work better than Spanish once or twice a week as far as retention. It's also way less stressful to me to have less subjects on my mind at once. Hopefully I'll let ya know how it goes!