It is inevitable. We will all run into a point in our yoga practice where more does not equal better results. My first experience of this, and probably yours, occurred in college economics and it is called the law of diminishing returns.
The law of diminishing returns (also law of diminishing marginal returns or law of increasing relative cost) states that in all productive processes, adding more of one factor of production, while holding all others constant ("ceteris paribus"), will at some point yield lower per-unit returns-Wikipedia
This is not just true for economics but can also be applied to the actions we take in our daily life. If you eat one piece of cake, you feel satiated. If you eat the whole cake you feel sick. If you work 15 hour days for a short period of time, you get alot done and are extremely productive. If you work them every day for an extended period, you get burned out and the quality of your work goes down.
The same goes for our yoga practice. There comes a time when practicing more often, adding more heat, and upping the intensity actually results in diminishing returns.
As yogis, we have to develop the ability to be present with what is going on with our bodies and totally acknowledge whether we are in the rapid growth, moderate growth, sustaining or diminishings point of our physical practice and practice accordingly.
Rapid Growth Phase- Your body takes a licking and keeps on ticking so you can possibly practice multiple times a day without problems. You havn't really reached your edge yet so injuries are not as common. Almost every class and practice is full of aha moments.You are building your book of knowledge and you always come away with new things to add to your practice. This is a good time to "go hard".
Moderate Growth Phase-You have a firm foundation in physical yoga. You understand your body and its edge. Regular classes don't really provide you with new information or advance your practice. This is a good time to seek out senior teachers , attend workshops and cultivate a strong home practice so they you can play with advanced poses on your own time. Recovery time is critical because you are already working at your edge during every single practice so the muscles need time to rest. Injuries are more common because you are already at your edge and it does not take much to push you over. To keep injuries at bay, it is better to work smart instead of just hard.
Sustainability Phase-You are a book of knowledge on physical yoga and you have reached most, if not all of your physical yoga goals. You purposely make a choice to practice in a moderate fashion on most days and push yourself every now and then when it suits you. You are at the point where doing more does not bring you better results. The body has been pushed to its limit. Injuries sustained during this period take a long time to heal. Recovery time is even more critical. It is best to conserve your energy for the few poses and skills that you still have not mastered. Your yoga practice has now hit a sweet spot where poses that are difficult to others, actually come easy to you. You have worked hard and you can enjoy coasting along on that hard work. Your practice should feel effortless.
Diminishing Phase- This is a time for innovation. What you are doing now, is no longer effective or maybe even necessary. It is time to reevaluate what is important in life and how you want to see the rest of it unfold. The internal effects of the yoga practice should have taken hold and you should be ready to embark on a new journey. What you do physically is all about preserving the basic functions you need to live a good life and to focus on higher pursuits.