I have been homecooking for my dog for the past 3 years, and I do follow the "balance over time" philosophy.
I make recipe batches of food which last between 4-5 days. I follow a recipe from the b-naturals.com site. So, for that period of time, she's getting the exact same ingredients. The next recipe, I'll switch ingredients (rotating protein sources, veggies, etc). For ex, I try to rotate between chicken, beef, salmon, sardines, egg (cottage cheese, yogurt, clams as just a % of the total meat portion), etc for the meat portions. For the organs portion of the recipe (I think it's like 10% of the total recipe amount), I may give some liver one week, and some kidney or gizzard, the next. If I give her any fruit treats (a tiny amount), I vary them. One day, I might give a bit of banana (potassium), another day it might be a bit of peeled apple (pectin), or a blueberry (acidifies; anti-oxidant), etc etc. I try do put in as much variety as I can, and I try to keep the nutritional value of the food in mind. I try not to overdo any one food type (ie, not too much blueberry, as my dog's pee seems to acidify VERY easily), etc.
The ONLY 1 ingredient which I make sure I have in every single recipe, is the correct amount of CALCIUM (needed to balance the recipe). But even though I'm balancing with the correct amount "in the recipe batch", once that eggshell powder is mixed in the food, there is no way to ensure she's getting the exact same amount of calcium, each and every day. But I DO know that by the end of the 4-5 day period, she has gotten the exact right amount. To me, that is "balance over time", just as with the rotating of the types of foods I feed.
Because I home "cook", I do make sure I add in plenty of supplements, to make up for whatever I may have cooked out of the foods. In addition to the calcium I put in her food recipe, I also give her a
daily mult-vitamin (as an insurance of sorts, to ensure she's getting all the needed nutrients her diet may be a bit lacking in),
omega 3 fish oil cap, a pinch of kelp, some extra B vitamin complex, and a probiotic. Those are the main daily supplements I feed at least 1 x per day.
Sometimes I'll add in a pinch of vit C powder (helps the immune system). And sometimes I'll add in a pinch of a whole food supplement such as Nupro Yeast Free (just to cover anything she may not get in the recipes), or I'll add in a little "topper" of RAW pureed veggies (carrots, romaine lettuce, parsley, peas, etc) for minerals and live enzymes -- but I limit the raw veggies because I don't want a lot of oxalate content in her diet, so her veggies are usually just boiled & drained. I sear her food in Canola oil, so that covers her omega 6 needs. If I'm just stewing meat, then I'll give her a Borage Oil or Black Currant Oil cap, for the omega 6. Or, I'll add in some Flax Oil to her food (omega 3, 6, and 9). I just try to keep things as varied as I can.
When I first started homecooking, I was going crazy trying to formulate a recipe "per meal" that would meet 100% of the nutrients she needed. I gave up. I don't eat that way; I try to eat a varied diet. So, I believe my dog will thrive on this type of diet, too. Kudos to those who are able to feed a diet that meets 100% of the daily required nutrients on a per meal basis, though.

But for us, balancing over time has worked. She gets a yearly blood test drawn, just so I can keep ahead of any potential issues. So far, so good.
hugs!
Pam & Sedona
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Note:
The author of the Whole Dog Journal article regarding homecooking and RAW canine diets, is also the co-owner of the yahoo K9 Nutrition group. I'm sure Mary would be more than willing to explain her views to anyone with questions. It's a very wonderfully informative group.