Rest is a major part of being healthy and it provides many benefits to everyone regardless if you are working out or not. Everyone's body needs some sort of recovery time so you can avoid getting any injuries in the long run. Resting your body will also help your body grow in strength and it will help you perform better when you go back to working out after taking days off. The rest will help you out in your other parts of your day as well since you will not feel burnt out and too tired to do anything. This is important for those who have 9-5 jobs or are students.
How to avoid it:
My favorite suggestion to you guys is to follow a weekly training split when working out since you can assign what days you workout, what muscle groups you are going to train, and the frequency of those workouts. If you need suggestions on training splits you can check out past Workout Wednesdays. I personally follow a four day split and tend to give myself 2 days off completely. If you are more of a runner whether it is on a treadmill or out in the street, always check your shoes to see if they are worn out since shoes tend to lose how much of the shock they take away from your feet after a certain amount of miles of running in them. My overall favorite suggestion is simply to GET MORE SLEEP. Sleep is so important for you even if you aren't working out intensely so you should always at the very least aim for EIGHT hours of sleep.
One of my personal over training stories involves me injuring my wrist from working out too much. A few months before I had started lifting weights I had slipped while playing a game of tennis which injured my wrist but by this point my wrist felt like it was fine. I didn't know why my wrist was starting to hurt again since the workouts I was doing didn't involve that much wrist activity I thought. Well after working out for a long time I attempted to do some dumbbell bench press with heavy weights and eventually after moving up in weight, my wrist starting hurting in the middle of a set and my entire hand gave out. The weight ended up dropping and hitting me in the chest but luckily for me though, I was fine and decided to call it a day after that. Ever since then, I have been much more careful about how intensely I workout.
Get your rest and avoid any injuries in the long run. Don't be an idiot like me and keep training even though you feel an injury coming through. Always remember to get some actual sleep time in, at the very least eight hours a night/day. And finally, structure your workouts to accommodate rest throughout the week and avoid over training certain muscle groups. If you need a weekly workout or a training split you can check out the past Workout Wednesdays and find one that fits your schedule or your fitness level.
Remember that this information is always readily available throughout the internet I just make it easier for you guys by telling you my personal stories and condensing the information into one post. If you guys are interested in some more information regarding the importance of rest and information regarding over training, you can check these links out and learn more: