From a nutrition point of view, replenishing glycogen, increasing protein synthesis and rehydrating are three critical components to maximizing your fitness but your post workout recovery nutrition also acts as nourishment to keep your immune system functioning properly.
To minimize risk for injury or illness, you may need to make some lifestyle changes (or investments) to ensure that your life allows you to recover, refuel, rejuvinate and repair between every workout but specifically after the more intense or high volume workouts. Endurance triathletes are known to squeeze in a lot into one day but sometimes you will gain more out of your workout by slowing down (and not feeling the need to rush to the next thing in life) and allowing your body to recover properly.
You will know if you are not recovering well if you find yourself with a run-down feeling in the 4 hours after training, you have difficulty sleeping at night (yet feel exhausted during the day), you can't give the effort that you know/think you should be giving during a workout, you are struggling to get through easy workouts, your muscles feel fatigued, exhausted or sore to the touch, your appetite seems a bit wonky or you have trouble reaching or sustaining higher intensities.
3) Recovery nutrition will not destroy your body composition goals. A common mistake for the athlete who seeks a change in body composition is not prioritizing the fueling and/or hydrating post workout all in an effort to lose weight. Keep in mind that weight loss in the form of reducing body fat (which is the kind of weight loss you want - not from water weight, muscle loss or bone loss) is dependent on expending calories or reducing calories and staying consistent with training so you can get stronger, faster and more powerful. Nail your recovery nutrition so that you can reach your full athletic potential.