If I think the person I'm talking to has unique knowledge of some obscure market or of cutting edge tech (the kind that comes from universities and labs), then

If I think the person I'm talking to has unique knowledge of some obscure market or of cutting edge tech (the kind that comes from universities and labs), then "yes" as long as the NDA is standard and isn't screwing me out of something surreptitiously. Otherwise, I'd think twice about it, not really because of the trouble, risk (there shouldn't be any) or the hassle, but because I'd question this person's entrepreneurial maturity or, um, view of reality? Everybody has an idea... execution is everything. In my early entrepreneurship, I tried to get people to sign some NDA-like stuff and I'm red-faced about it to this day. It was unnecessary and made me look like an amateur.