Like almost any other question about fitness or running, the answer to this question is a little bit more complicated than a simple yes or no.
The short answer is that it depends on your current level of fitness and your goals.
The frequency of your running workouts should ultimately depend on what you're aiming to achieve. It's important to follow a training program that's designed to match your current level of fitness and that will effectively and safely help you improve your abilities.
Some experts might argue that it's not a good idea to run every single day of the week, especially due to the fact that running is an extremely repetitive motion. By performing the same activity day after day, you may increase your risk for an overuse injury by repeatedly engaging the same muscles and joints.
That said, so long as you are in adequate shape (e.g. you've been running consistently for a year or so and have built up your endurance) and you follow a sound training plan that allows for sufficient recovery time between workouts, there's really no reason why you can't run every day if you want to.
"I think it is healthy to run every day if you have a healthy passion for running and racing," says Deena Kastor, Olympic medalist and current U.S. record holder for the marathon and half marathon. "It is critical to balance hard workout days with some hardcore recovery runs, but if you are a 'no pain, no gain' runner, then a day off is vital."
In other words, if you balance the intensity of your daily workouts and make sure to include easy, recovery runs between your tougher training days, then running every day is totally OK.
But if you like to run at full speed and hardly ever incorporate slower workouts into your routine, then running every day is definitely not a good idea.
"Recovery is just as important as the workouts," says Kastor. "I take recovery in between repetitions, take recovery runs at a pedestrian pace and take a month off of any type of working out every year."
She went on to explain that focusing on recovery is important because it will benefit your mental health, balance your hormones and allow your muscle tissue to repair.
"I indulge in the restoring process and think it is the most significant factor in my longevity in this sport," she said.
The bottom line: if your body is prepared to handle the workload and you make a point of treating it gently and with care, there's no reason why you can't run every day. Just make sure to take breaks when you need them and most importantly, make sure to maintain your enjoyment of the sport.