In taiji like in other practices, we tend to want to take in all the material at once. This is impossible as the requirements of taiji are extremely difficult to put into practice. The problem is that if we focus on too many things at once it become too difficult to negotiate all the rules.
It is actually better to work on one rule or one lesson at a time, until it is ingrained. When the body assimilates the rule, it is time to add a further one.