No, there is no time limit on learning. 
Feeding is simple, but sorry, no cliff notes on educating yourself. 
Flower, you've made a couple of very good posts in this thread....especially the one about dogs being carnivores. I will admit, I was trying to lead you with that question and you shot me down...in a ball of flames. Very good.

I will say I don't disagree with an owner who is willing to take the time to formulate a "homemade" (I'm changing my terminology here for Knny's benefit) diet that is nutritionally complete for their pets. The one problem I've encountered with it is the same one I mentioned before, owners, when using these types of diets MUST take the time to formulate a diet that is nutritionally compete for their pets. Nutrition will not be the be all or end all for preventing disease, but it will help, and considering the recent pet food recall, is something that needs to be looked at very closely by both veterinarians and pet owners. A well formulated homemade diet is great. The problem comes with owners who do not take the time to do that and who cut corners or they stubbornly cling to unfounded beleifs that result in nutritional disease in our pets. Nutritional diseases encountered amoung our pets in the 1930's and 40's have been virtually eliminated with commercial dog foods (I'm refering to ricketts, metabolic bone diseases, and other gross nutritional imbalances). Unfortunately it appears as if we have come full circle with commercial diets where the manufacturer, or worse yet the manufacturer's suppliers, have managed to cut costs (and enhance profit) in a way that has resulted in the deaths of many family pets. Its a sad case of the dollar governing things once again with little regard for who or what is hurt.
The other big problem is human laziness. Lets be honest, people are lazy. Thats why ready made meals are such big sellers. If a person won't cook for themselves, how can you demand that they cook for their pet? It just doesn't happen that often.
One study I'd like to see involving homemade diets is the incidence of obesity in relationship to the dog eating only a homemade diet and a dog fed a commerical food with "table scraps". I'd also like to see the incidence of obesity in domestic cats allowed to hunt (or conversely a diet composed of whole rodents, other mammals and birds---a comparative small cat "wild" diet) as their sole source of food vs domestic cats fed commercial cats. I'm not aware of such a controlled study existing, but I'll also admit I haven't taken the time to do a full literature search on it.