Of course, we need to do the research so that we have adequate information. We will never have all the information available, but we can gather what we realistically need.
Once that is done, we make the best decision we can. That is all we can do.
It does not do us any good to second-guess ourselves afterwards. Hindsight is always 20/20. Rather than wasting time and energy on beating ourselves up for a making a “bad” decision, we can learn what we can from it and move forward.
If we made the best decision that we could with the information we had at the time, that is all anyone can do.