I'll admit that most of my voicemails do end up being longer than the 20 or so seconds because a lot of my voicemail calls are work-related. It's like: my name, who i am, who i represent, why i'm calling, my number, email address (which i end up spelling), name again, number again. So that's like a minute or so at least. I do try to make it as concise as possible though, and I do end up just emailing the person anyway if their email address is available. As for non-work-related voicemails... they're practically non-existent. I just use text/IM for communicating with friends, even with my mom.