Let me start by saying I don't think building an app is a bad idea. Apps are a huge part of our culture today and as mind numbing as it can be to be introduced to yet another CEO of X app, it's not a trend going away anytime soon. What I do think, is that you probably don't need an app to be successful, or to show proof of concept.
CEOs are the new celebrities. You hear more about Mark than you do about TV actors, and people like my friend, ZuckerbergDan Price, are making headlines about their corporate culture. While this is a welcome change, entrepreneurs are often glorified in ways that aren't representative of the time and work that goes into starting a business. Young or aspiring entrepreneurs often get the wrong message and make massive, expensive mistakes, like building an app they don't need.
Here is how to know whether or not building your app is the best move for your business:
1. Proven Model
If you have not yet built your version of your company, you shouldn't start by building an app. I'm not talking about whether or not you have wireframes, I'm talking about whether you have done your due diligence or not. That includes things like customer and potential customer interviews, generated your first sales (or promise of them) and researching your competitors.
2. It can be done with a pencil and paper
You can come up with a million excuses about why you can't do something without technology, but there are truly only a few instances where that is true (if you are building a rocket for example). Some huge startups you've heard of (and probably use all the time) pulled the Wizard of Oz trick and did everything manually behind the scenes. Sure, it looked like it was automated, but their MVP was not.
A company you are very familiar with did over 1,000 deliveries a day by using text messaging and an excel spreadsheet. "I can't" simply is not part of an early stage startups vocabulary.
3. You don't have anyone technical on your team
Tech is expensive. Very expensive. If you don't have a background or have someone seasoned on your core team, it's not wise to start building something. There are only a few truly great tech agencies that translate your idea properly but most of the time, the disconnect between tech agency and founder are wide. Which brings me to my next point...
4. Technical debt
Coding is extremely complex. Think of it like Jenga, or like building a house. You have to build up from the foundation. In startup mode, you are working quick and dirty, so sometimes that means skipping over steps you may or may not know you need in order for your product to work. Or, you excluded a feature you didn't think you needed and now you have to tear down the existing house (or pull a delicate Jenga block) in order to add it back in. Now, you have wasted you money, and a lot of time.
Most of the time, your customers are the ones who will dictate features. Wait for their feedback.
Like my previous point, you probably think you've thought of everything, but I promise you, you have not. Don't put out a product until you can start using it to build upon customer feedback.
6. Raising capital
I constantly hear people say they think they need their app to work in order to raise capital. Wrong. You need traction to raise capital. If you spend a small amount of money vs. hundreds of thousands of dollars, and are doing as much as possible with what you have to show traction, you're way ahead of the game.
I could continue for hours about why you might be wasting you time building an app, but the major point is this. If you don't have to - and be very honest with yourself - don't do it.