What's the proper way to tell if an object is allocated in Objective-C? 

I've seen in sample code (and this seems to work only if it's never been allocated):

if(!Object) { ... }

I've also tried setting Object = nil, but that's a tedious process each time, gets a little bit annoying. 

But if I have an object, and I want to allocate and release it more than once, what's the proper way? Thanks!