Have them break it down for you. Creating a LLC is one thing, but what's the exit strategy? What state will it be registered in? Is it going to be just one company or layered? Are you both going to have to put money in to establish equity? Does starting the business start a specific timer they are concerned about? What does your partnership contract look like?

If they have gone through it before, it's probably the exit strategy. How you set up the company and what state you register it in can impact your value to potential purchasers (and how easy it will be to transfer ownership).