There is no one correct answer because there’s an inverse relationship between intensity and frequency. The more intensely you train, especially with weights, the longer it takes for you to recover. Hence you cannot train too frequently. Likewise, if you train especially frequently you will probably find you are not capable of performing high quality work at the degree of intensity you might expect, but you may be capable of practicing low-intensity endurance or mobility work.
Your ability to recover changes over time. Not only is it dependent on how you sleep, your vitality, and whether you’re eating enough of the foods that agree with you, but it also changes in response to your age, your ‘training age’, and for any number of other reasons, both known and unknown. Some people become better at recovering the more they train and over time, they find they can train more frequently. But this, like everything else, starts to plateau sooner or later. And if you overdo it, you will notice a decline in your ‘performance’, so-to-speak, and you may need to take an extended layoff.
I read once that the condition of your central nervous system reveals itself to you, through your own sense of enthusiasm. You know when you’re not ready. There is no point in wasting time at the gym.
Eliminate concepts. Train when you’re ready. Do not train when you’re not.