If, for some archaic but occassionally useful reason, you are going to leave a voic email message for someone, leave a short but informative one. And if you are cold-calling and we (the world outside your world) don't know you from a can of paint, then be smart about your communication. The smart communicators leave their telephone numbers twice. The wisest folks leave the number at the beginning of the message and at the end of the message (that trick I learned from Maeshay, who used to work here at AKILA WORKSONGS).
If you're speed talking when you leave your voice mail message, you do know that you force us to rewind the message, right? First, we don't like analog but we know that it's necessary. Secondly, we certainly don't have time to rewind messages just to get a number right. Please, either say it slowly or say it twice. You will stand out if you do...which is a good thing!