If companies charge in a somewhat substantial manner for their App or service they are more likely to be in for the long run. This is why products from Panic, OmniGroup or Basecamp are good investments, for example. The comfort of knowing that their products are around for a while tells you that it is worthwhile to invest time to learn them and to assume that you do not need to migrate your data during the next 12 months. But longevity comes at a (higher) price for makers and users alike.
Whether it is a big price tag, at least relative to the omnipresent 99 cent Apps, or a limited freemium model with subscriptions unlocking the true value: It is typically a signal for a sustainable investment to me. Maybe this is an over-simplistic approach, but it has served me well so far.
Makes sense to me. I think I actually do that but don't even realize it.