To live according to Halacha, you do not need to be able to pasken the questions that arise. You need to understand the general idea, and have the ability to discern when to ask further.
In Hilchos Niddah, which has been raised as an example, you can buy any of a number of excellent seforim in english, spend several hours studying it, and voila! You know how to live your life, and when to ask a question.
Further study would be “necessary” only as the mitzvah of talmud Torah.