Even though I'm a native English speaker, I discovered right now that I didn't know what prudence meant. I knew the word prude so I naturally assumed that prudence meant being concerned with morality and sexual behavior.
It turns out that the words are unrelated. Prudence means the ability to govern and discipline oneself by the use of reason. So unlike prude, prudence is actually a positive trait.
Though I'll add that "in modern English, the word prudence has become increasingly synonymous with cautiousness; in this sense, prudence names a reluctance to take risks." (Wikipedia)
I'd have expected them to be a lot more decadent and care free. Maybe it has to do with being raised by a generation that could not be decadent or care free (by and large).
Indeed, as at least the perception of prosperity goes down, it’s worth observing that millennials have fewer sexual partners than boomers and use less drugs.