Research from app analytics firm Localytics has shown that, rather than attempting to monetise freemium and free-to-play users as quickly as possible, developers are better off ensuring that the customer is fully engaged before offering any in-app purchases.
The study shows that a large proportion of users, 44 per cent, will use an app at least ten times before they're willing to invest in any microtransactions or in-app purchases, with just 22 per cent investing cash on the first play.
Furthermore, those players who do wait until they're fully engaged with a title tend to actually spend more on the game in the long run, whilst many of those who pay first time will move on without spending much, or even any, more. Customers who don't pay immediately spend, on average, around 25 per cent more over the course of their game playing.
Previous research by the firm also indicated that around a quarter of all apps are only used once after downloading, highlighting the problem of 'throwaway' culture which plagues many freemium and free-to-play titles.

http://www.gamesindustry.biz/article...-app-purchases