I would say you put yourself at risk to have wasted the 5 to 6 months of programming. For some applications the risk is low or the possible loss acceptable. A

I would say you put yourself at risk to have wasted the 5 to 6 months of programming. For some applications the risk is low or the possible loss acceptable. A preferable approach is if you can test the business/app soundness before investing 5 to 6 months in programming effort. If you can test two or three app ideas in that same period you significantly increase your chances to hit gold.