Xfce does not start gpg-agent at startup, this ends up with programs like evolution asking the user every time his key pin. AFAICT this only appears with >=gnupg-1.9
Created attachment 2607 Patch to launch gpg-agent on xfce login The attached patch implements gpg-agent similarly to how ssh-agent is implemented.
Oh, didn't know about this bug. I implemented this in xfce-utils git master a month or 2 ago.