Mobile users are quick to discard iPhone apps, with just 30% of buyers using them the day after buying and downloading them from Apple’s App Store, according to a new survey.

The drop-off rate is even higher for free apps, with just around 20% using them the day after download, and less then 5% 30 days later, with games apps the most durable category.

Pinch Media has revealed these figures after studying 30m downloads of iPhone apps. Its slideshow presentation ‘AppStore Secrets’ is available to view here.

Paid apps usage over time

With more than 20,000 apps available to iPhone users, many of which are free, the drop off in usage is not so surprising. It takes a well designed and useful app to keep users interested.

I’ve downloaded many more apps then I’ve used regularly and it’s only useful and entertaining apps like Last.fm, Twitterific, Shazam and Yelp that have me using them on a regular basis.

These stats on iPhone app use have consequences for both developers and advertisers; the survey recommends that most developers charge up front for apps to guarantee an income as the drop off in usage means that using a free, ad-supported model is risky.

For advertisers, the study concludes that less than 5% of iPhone apps are high performers with continued usage and are thus suitable for advertising.