We all exercise at different intensities and recover at different rates which makes super specific on Monday-do-this on Tuesday-do-that guidelines flawed from the outset.
So if rigid guidelines don’t work what can you do instead?
Use your workout performance as a guide
If your exercise performance is increasing from one workout to the next you are probably resting for long enough. If your exercise performance is decreasing from one workout to the next then you are probably not resting for long enough.
Obviously there can be blips along the way and outside of the beginner demographic I'm yet to meet someone who improves every single time they perform a workout. Instead base your decision on positive or negative trends over the period of a few weeks.
Performance increases, workout frequency is good. Performance decreases, workout frequency needs to be addressed. Using this simple philosophy you can quickly fine-tune a training schedule which works well for your own exercise intensity and recovery capacity.
As an example I’ve recently been trying to improve my pull up numbers which had been slipping for a while through lack of practice. I started out including pull ups in two workouts per week, performed to max-effort each time. Initially I made some progress, then the numbers stalled and actually started to reverse.
The solution? I dropped a workout and went from training pull ups 4x per fortnight to 3x per fortnight and my numbers started to increase again.
Remember, exercise is the trigger not the benefit. Adaptation to exercise is the benefit. If in doubt, rest more!
(Of course this assumes you worked hard enough to trigger an adaptation in the first place)