Most individuals should aim to workout three to six days per week. This will vary from individual based on factors like age, current body conditions, past experience level, ability to recover from workouts, and sleep.

Programs slowly scale in difficulty to continuously adapt your body. So the first one to three months you may start with twice to three times per week weight training and one to two days of light impact aerobic cardio and then as your body adapts your workouts will become more intense and more frequent. You should stick to the same program for at least 2 weeks but no longer than 6 weeks. This ensures enough time for you to learn the exercise movements, and muscles to adapt, while still challenging your body to make progress. 
 

Factors like, how hard do you train? – dependent on one rep max percentage (1RM%), Rate of Physical Exertion (RPE), and volume in the gym (number of sets per workout) will all affect the amount of physical stress your body undergoes.  

 

How are your joints being taxed? That depends on your exercise selection. - free weight vs machines - fast explosive tempo vs slow tempo - lightweight vs heavyweight. 

 

What physical activity do you have outside of the gym? – occupational activity? Free time activity such as recreational baseball team or an avid gardener cutting? etc. 

 

The discipline of your diet. Quality of food.Your sleep quality. Your time sleeping. Your ability to recover.

All these factors and more will affect how often you can train. I will leave you with there is no such thing as overtraining, only under-recovery...