What you can only do is waiting to the time when your project will be finished, you can only hoping that it will be good as expected. And usually it takes from 3 to 6 months.

You waste your time by doing research to decide whether to use in house developer or outsource it to software house, if you use in house developer you waste more time to search candidate, train them, provide them with every equipment they need when the time it finish, you'l be very exhausted and still you have a lot of work to be done selling your product and make sure your app work without error.

But if you chose to work with software house, again you will waste your time searching for the best partner, negotiating the price, searching for quality. The more you search for the fittest one, the more you running out of time. But if you decide too fast the more fear and uncertainty you get, and then when it finished you realize that your user behavior is different than what you predict and you want to modify your app but you have to start it all over again, negotiating, meeting to make sure the design work then waiting at least a month or more.

Your cost will be unbelievably expensive without knowing that it going to work or not.

You have no control except for what you've agreed upon

You can change you design anytime you want, you can determine what to do first, you can discuss your ideas at anytime when the project already started, you can actually engage in the developing process if you wish or just let us do it for you.

You can save more time, energy and money. More than that, you can measure how far will you go before you change the course and before you spend it all out. "Fire bullets, then cannon balls" - Jim Collins

Your cost will be unexpectedly cheap and you can test and measure every step you make before you go further.

You have control but less obligation to manage multiple resource.