I've been using DevStudio for far too many years now and it always amazes me just how many programmers don't know about the memory analysis tools that are available in the debug run time libraries. Here's a few links to get started with:
Tracking Heap Allocation RequestsTracking Heap Allocation Requests - specifically the section on Unique Allocation Request Numbers
Of course, if you're not using DevStudio then this won't be particularly helpful.