When I first started training, I didn't work, I trained 2 times a day almost everyday. This worked great for me for a good 2 years, I progressed fast and learned a lot. Unfortunately, at my age, my body started complaining. I suffered a few good injuries and started feeling very tired. I have learned to listen to my body and know when to say enough is enough. I have also learned the difference in feeling exhausted and run down and feeling lazy!
Last night I wasn't feeling great and my body was aching and bruised from the previous few days. As I was driving to the gym (with an ice pack on my neck and bathed in Icy/hot) I was thinking "maybe I should take tonight off" all I wanted to do was lay down on the mats and sleep! But, after about 15 mins of warm-ups I felt so much better, my soreness was gone and I had a great night of training and I actually feel better today then I did yesterday.
Listen to your body! But, also learn the difference in sore and injured or completely exhausted and feeling lazy!
I'm not saying to "over-train" but, push yourself! And push through being sore and tired!