Soreness is good. Not only is it validation of your previous day’s work, but it also is an indication that you’re getting fitter.
But reaching and staying “fit” doesn’t require that you always walk around sore. Rather than using a subjective metric like soreness to determine your workout efficacy, I would suggest an objective one like “# of Consecutive Days”.
Sure, intensity is the shortcut to results, but not at the expense of missing tomorrow’s workout. He or she who works out 5-6 times a week will always be happier with their results.
But when you have pain, pay attention to these two things:
First, is the “pain” you’re feeling in the joint or muscle? If it’s in the joint, you have an acute injury that needs some attention. If it’s in the muscle, it’s soreness. But you can (and should) continue to workout! Most of the time joint pain requires us to simply modify the movement, while muscle pain requires us to scale the movement.
Second, is your soreness causing mood changes or significant fatigue? This happens to me every month or so. If it is, this is an indication that you’re overtraining. When this happens, take the next day off from exercise.
These are small considerations on your path to fitness. In summary, I would follow James Clear’s mantra when it comes to developing any healthy habit: Become the type of person that never misses two days in-a-row.
If you can do that, you will be happy with the results.