It is important to rest after training so you allow your body to recover. It is often misunderstood of what it means to rest between training days.
The basic rule of thumb is that you should rest 24 hours before training a specific area of the body for a second time.
This means that if you train your lower body on Monday you can train it again on Tuesday. As long as wait about 24 hours you will be okay.
There are a few things to consider though:
1). Training more often does not mean that you will progress faster. There are diminishing returns to training and the more you train it will not necessarily transfer to more results. I would recommend training everything in the body once or twice a week.
2). Nutrition pays a huge roll in your ability to recover so keep that in mind as you plan your rest days. If you have poor nutrition waiting longer will would be better for you.
3). Soreness is not an indicator of progress; nor should soreness in a muscle group deter you from training it. However you should be aware of excessive soreness as this is a sign of overreaching (Click Here).
Listen to your body; if you feel good to train then do it. If you feel too sore or lacking motivation take an extra day off.
Dedicate & Succeed,