An app is never complete – that’s our view. An application, like any piece of software, needs to be regularly updated and maintained. Don’t be afraid to pull features out – if they’re not adding value, why have them? You can get some pretty in depth stats on how users interact with your app (we use Flurry for our analytics) so make sure to scrutinize what users like, and what features people don’t use.
Having said this, development should be a gradual but ongoing process – don’t try and cram every feature into your first release – users are unlikely to even find half of these. Instead, start off with something simple and useful, and slowly add updates. Be careful about updating too often though – If you see the little 1 badge on the App Store app for the same app all the time, users might question what is wrong with it that it requires such frequent updates. Somewhere around 4-6 updates a year seems reasonable.
So, when you start development, make sure you have a plan and the budget to continue to support and update the app – add features that are going to be useful, cut those that aren’t, and always ensure you are adding benefit to the end user.