I have always thought that the virtue of prudence is very closely related to wisdom, although less about what I think and more about what I do. When it comes to speech, it means knowing when to shut up and when to speak up. Personally, I have always weighed in on the side of saying too much rather than too little--according to my brother, I have an overdeveloped sense of honesty...this means that I often feel like I am lying when I am merely not telling the whole story. This can be a legitimate offense, as we can lie both by omission and by commission, especially when we refrain from saying something in order to make the person we are talking to believe something that isn't true.
I did this with my ex when I hid my hours in Adoration because I knew he would disapprove. I also did this when I didn't say anything when I was unhappy in order to keep the peace....All I did was compound the problems we were having because I was saying with my actions that everything was just fine when it wasn't--I felt incredibly guilty about it, as it felt very deceptive to me, but in my lack of wisdom, I didn't know what else to do. I suppose it is always possible that saying something could have changed the outcome, but then again, maybe not. I remember mentioning to my ex that I wanted us to go to counseling again three or four years before we split up, and his response was, "we'll think about it." If nothing else, I have learned the hard way that full disclosure is better than letting things fester, so I will always probably err on the side of over-disclosure.
One can be imprudent in the other direction as well....no one really wants a blow by blow of the minor surgery on that abscess you had on your knee, and not everyone needs to know your innermost thoughts on the mating habits of the north american tree frog. (I don't have any, by the way....) And, sometimes it is all about timing....Christ didn't tell his disciples everything because he knew they couldn't handle it at the time. In John 14, He talks about how the Holy Spirit will come to guide us into all truth. It isn't that Jesus didn't trust his disciples, but that he knew they weren't ready YET.
At the same time, John 8:32 says that we will know the truth and the truth will set us free. I think that I am still learning what it means to be prudent in my words and actions, as the pendulum has gone from being too silent to too open again. And, when that happens and it comes to my attention, I will likely delete posts. I don't always get it right the first time, but with God's help, I DO eventually get it right!