Choose when enough is known, not when nothing remains unknown.

There is a difference between having enough information and having all of it, and only the first is achievable. Setting the second as your standard means you will always feel unready, no matter how much you learn. Sufficiency has to be defined in advance or it will keep moving.

Before researching, write down what you would need to know to decide. When you have it, decide, even if new questions have appeared in the meantime. New questions always appear; that is not evidence you were unprepared.