Average Selling Price _ Now when you calculate your average selling price which is your cost of sales (material + labor) divided by Ƒ_gross profit), you can determine how many customers you would need and then come up with what you think your conversion rate would be for converting leads to customers, you can determine how many leads you would need. Then from this and with the aid of the U.S. Census Bureau and some basic research on your own you can actually have a pretty decent idea of what size your market is and is going to be in the future so you can see if it will support your business plan or not.
When writing a business plan you sometimes end up locking yourself away. You might have unique ideas which lead you to seek some isolation and secrecy, or if you are going to be a sole trader you may only have one person to consult namely yourself. But it is fantastic to try and get broader input on your business plan _ whether from a professional, or simply from friends and family whom you trust. I say that because of course you need to be careful with commercially sensitive ideas, as you do not want to pass your plan on to someone in the pub who then starts your idea before you across the road.