While testing and debugging your app with XCode you can use this logMemUsage() function to NSLog the used/free space and watch how things are going while you test your app. This function logs any change in usage > 100kb. It outputs to the debug log like this (on the simulator the free space is huge): 2011-11-02 21:55:58.928 hello[971:207] Memory used 21884.9 (+21885), free 1838366.8 kb 2011-11-02
![Watching memory usage in iOS](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)