When to close WCF client?

[MBursill]

When is it a good time to close a WCF client? Straight from MSDN: http://msdn.microsoft.com/en-us/library/ms751519.aspx[^] It shows:

CalculatorClient client = new CalculatorClient();

followed by a bunch of calls to the client, and lastly...

//Closing the client releases all communication resources.
client.Close();

What I really want to know is if it's an okay practice to keep a client open for long periods of time, possibly indefinitely? The reason I would want to do this is because I call a method on my service named "AuthenticateUser" and later I wish to call "GetAuthenticatedUser". If I use the same client object, my returned User object is persisted (without the need to implement a stateful service). I'm having a hard time finding information on what is and isn't good practice when it comes to WCF, specifically on the client side. -Mike.

[mohit raghav]

did u find the answer for it??? s26f84 at gmail d0t com thanks