IPad allowable memory pool

I am curious as to what others have been seeing in regards to overall memory allocation strictly on the iPad. When are you running out of memory roughly? And is there a base guideline on allowable? I am seeing some varying results so I was hoping to see what everyone elses experience has been.

I am struggling with a pile up in memory currently I can’t solve. It shuts down at about 70MB according to the Xcode Instruments graphs.

HTH
BTH