The lifetime of an instance of a WCF service?

Question

in the process of creating a WCF service I ran into a term that\'s new to me. Basically when specifying the InstanceContextMode I have a few options, including;

Answer 1

Yes, sharing the service instance means that there's only one instance created by the server, shared between requests.

In particular, the constructor of the service object will be called once, when the instance is created. This can be important for example if you use some form of authentication with impersonating the context's identity (shared instances could potentially require some extra work to handle such case).