When should we not create Assembly's strong name? What are the disadvantages of "strong named assembly"?

I have a project, i.e. library.exe. In this I have referenced an assembly (logging.dll ver 1.0.3.0) and I have given this assembly a strong name.

Now suppose I changed a method in logging.dll and made version 1.0.4.0.

Now when I copy/replaced the old DLL with this new one I got an exception. I know that exception is because I have changed version number of the DLL. As it was a strong name DLL it's not allowed unless I rebuilt library.exe.

What I want to say with above story is

1. Use strong name with assembly only when we have to add it to GAC.
2. If we have an application where individual assemblies requires updating do not use strong named assemblies.

Am I correct with point 1 and 2?

When should strong named assemblies not be used?

What are the disadvantages of "strong named assembly"?