Very few developers have proven that they're capable of building a sustainable business (like e.g. OmniGroup). It's impossible to say if a particular app will

Very few developers have proven that they're capable of building a sustainable business (like e.g. OmniGroup). It's impossible to say if a particular app will in a week: a) still be available b) if it will have switched to subscriptions or free + IAP or free with ads and IAP c) what the IAPs will be and if your old (if any) IAPs will still work. d) if they'll decide to sell your info to the next available bidder This is why almost all apps are worthless and why I've essentially stopped purchasing or downloading apps. It's simply not worth the trouble to invest time to learn to use an app and investigate whether you can trust the developer.