How much you do any activity is dependent upon intensity and how this applies to your training goals. There is no way to take the number of training session into consideration without it's appropriate relationship to intensity, volume and ultimate training purpose defined with periods of recovery included into the equation.
Another thing to take into consideration is the fact that no two individual physiology is the same. We don't recover in the same way. Or, train effectively in the same way. You have to play with your training schedule to find out what works best for you.
Keep in mind that blood volume begins to drop with only a couple days of inactivity (i.e. rest) but if your rest days are not back-to-back, this would not be an issue.