Three thoughts on this:
First, as a career R&D type, the very best ideas to patent are those which no one would ever think of but once you explain it to someone versed in the field the advantage of doing “it” that way is not just clear but compelling. Absolutely essential not to discuss an idea like this without an NDA, until the patent is filed.
Second, as someone who spent 15 years in big company tech business unit “chief technologist’s offices” and during that time was part of taking a first look at between 100 and 200 companies that were trying to sell either their tech or themselves to us: the best practice for a first conversation is a clear agreement that there is no NDA, and nothing considered confidential will be brought into the room. This frees us to have the most appropriate people see the presentation, without concern about contamination.
Third, there are times when it’s cheaper and easier to just sign the NDA than to debate or negotiate or walk away. I remember talking to a reseller for one of the biggest names in the software industry, who simply signed and returned a rather one sided legal document rather than even have his counsel review it. While I don’t remember the exact words, he roughly said “…they can already put me out of business any time they want, so there are no consequences to me signing this…”. Or in my case, I was asked to sign an NDA before a job interview at a world class tech hardware company a couple of months ago, and in thinking about it realized I’m so used to compartmentalizing the confidential information of other companies that the NDA only asked me to do what I would have anyhow. So I signed.
It’s essential to use NDAs when dealing with subcontractors or contract manufacturers who will be exposed to trade secrets. Or who would have access to your entire code base.