When I started running 6 years ago recovery was the last thing I thought about, I just ran. I focused on improving my pace and becoming an efficient runner. It was just me and the pavement (and the occasional trail). I have found one can bounce back easily at 23 years old but pushing 30 is another story. Recovery is now the most important process in my training. I have read many articles and books which conclude recovery is different for every individual. My recovery is fairly simple; 20 minutes post run I have a protein shake + a carb (normally fruit), a tsp of fish oil, coconut water, stretch, ice, and put my compression socks on. Protein aids in muscle recovery. Running is a repetitive motion which tears muscles apart due to mechanical stress and free radicals. Protein rebuilds muscle to their maximum efficiency. By adding a carb with your protein shake it will allow your muscle to adsorb the protein more efficiently (carbs spike your glucose levels making protein abortion easier). If I run at night I incorporate a sweet potato with my dinner. I top it with honey (a natural anti-inflammatory) and cinnamon (because it tastes good). Sweet potatoes are loaded with potassium (an electrolyte), vitamins A and C (helps the immune system). Long runs can suppress the immune system initially but over time aid in strengthening the immune system. Recovery is one of the most important training elements. Recover properly and you will never have to take a day off. Happy running!
More info about protein: http://www.strongerfasterhealthier.com/blog