Limits to storing data on the iPhone via an app

For the first release of my app I want to store all information locally using plists. What would be the limit to the amount of memory my app could use up on the phone?

In other words, the user will be continuously be storing data on the device via my app 开发者_Go百科and in plist format. At what point will the app not be able to store any more info? I would imagine this would be caused by: 1. storage limits on the device and/or 2. limits that apple places on each individual app.

You can keep storing data until the storage on the device is full, but it would be nice to purge old unneeded data from the device once in a while.