the formula is "optimum stress + optimum recovery = optimum progress"
Optimum stress means putting the right amount of "stress" on your body, be it through high heart rate, high intensity interval training, strength training, speedwork, or zone 2 long slow distance. the right stress at the right time. Apply too much stress, and you risk needing many days for recovery, with visits to physio and chiro.
Optimum recovery means not only allowing time to heal, but not doing too many hard workouts too many days in succession, aiding healing through yoga, stretch and roll, massage, and getting lots of sleep.
The workout is what tears you down, wears you down, it actually makes you weaker. The recovery is where you adapt and become stronger. Therefore the recovery is as important as the workout.
