Training the same muscle group days in a row?

I’ve always followed the FB advice of not training the same muscles (especially if they’re sore) back to back everyday. To give that muscle group semi rest for at least 24 hours.

What is the reason for this? Is it okay to do if you’re not at all sore?

Im just curious what the science behind the recommendation is. I recently saw some new fitness “advice” about not following that recommendation and they stated different reasons.