If your product is creating new market then consider how long will it take to close a deal. If you plan to have a MVP in 6 to 12 months and closing the sale can take up to 6 months (in our industry it can take that much) then you need ~18 months (you can start selling your idea, pitching, seeing your potential customers - in such case this time can go down). Also your money pot should pay somebody to do sales, marketing and operations for you (unless of course you do it yourself).