Have you joined my free Facebook group? If not, you should! JOIN NOW

USABLITY: Is it beneficial to have a contact form on your home page, and every page of your site?

Forms are ugly, and even if you make them small so as not to take up too much space on your page, they’re still ugly (and short forms tend to invite tyre kickers).
As long as there’s a prominent link to your contact form in your navigation and in your sidebar. I think that’s sufficient, but it comes down to personal preference (and your own tests).