When recruiting the founding team, should we use NDAs?

In short, you should. If you want to have any legal remedy against a potential misuse of your confidential information (e.g. to create a rival business) then you should put some deterrent in place. Remember that until they are in you team, they are effectively complete "strangers". From a legal point of view, there is also another aspect to consider. Most countries would consider a non-accidental disclosure of confidential information as prejudicial against protection of any rights you might have in that info (e.g., patents) so an NDA would help preventing that. I would also suggest using a one-way NDA if possible as that would not put any tie on you. From a practical point of view your should also ask yourselves: what do I need the additional founders for? Is it for their technical ability, their financial backing/nous, their sale experience? This should help you deciding what info you really need to disclose to them at first, and what you could keep until more "commitment" comes from them. I suggest you get in touch with a lawyer to help you going through the documents and assist you with your next steps.