Most valuable piece of info here for App developers: Make your app universal. It doubled our sales.

If your thesis is that you'd be better off as an iOS contractor than making your own apps, then you might be right. But this was our first app, and my partner went from someone interested in design to being an actual designer as part of this experience. I consider that alone to be worth more than $89,250, because it is a multiplier on what we have been able to do subsequently.

Also, the first months this app was doing around $200 a month. It took effort on our part to change that. We have done multiple things that caused the sales of our app to double as a result. In fact, every major release of our app has caused sales to double. In fact, this leads to one of the big secrets of the appstore. There are 600,000 iPhone apps but only 200,000 iPad apps. We get equal sales from the iPad as iPhone. We stared out as iPad only, then added iPhone- boom, sales doubled. (I was hoping for a triple or more because there are so many more iPhones, but alas, no.) Make a real universal app, you'll do better.

I believe there are some things we could do that would double our sales a couple more times-- for instance adding some social aspect to the app, adding iCloud support might both result in a doubling, which would throw your numbers off for the comparison.

I didn't put this app out as an example because I think its an example of what one could potentially make-- I put it out there as an example of what could happen if you do an app that never makes it into any of the top lists or gets any marketing. It was meant as a minimum example, not a maximum example.

This app is was also an experiment and has been used as such. It would have been easy to put out a revision in the last year (and there's a feature we really need to add) but by waiting a year we've observed how not updating the app has affected sales. Now when we put out the revision we'll be able to confirm our hypothesis about past revisions.

I expect this app to continue paying out this dividend for the foreseeable future, which I'd say is about 2 years.

This "dividend" is completely dependent on the way Apple markets apps to people. We don't show up on any lists. When Apple changes their algorithm, we feel it, much like google changing their algorithm impacts websites. So far, Apple has been changing the algorithm to highlight quality apps, and that's a good thing so this has benefited us, but at some point we may run afoul of one of the rules in the algorithm. (the one year without an update was a test to see if there was a rule like that-- and I think there is, I think we've been punished for going so long, but the slack has been taken up by growth in the total addressable market.)

With any business effort the question really isn't whether "apps" make "money", but how much leverage you get. What makes money is work and smarts, right? You can spend X amount of time and make Y amount of money a year building a SaaS Website, or building an App or working a job. Apps give your more leverage than SaaS Websites which give you more leverage than employers-- but that's just a generalization. It really depends in part on how well you understand the market, but also a great deal on how much effort you put into it.

I was pointing out here that we have an app we haven't put much effort into that has made rather good money given the level of effort.