I would guess I am about 60% home brew. I buy a fairly substantial amount of commercial beer because I like to try new/rare offerings from local breweries or when I travel. That being said, a lot of the commercial stuff I buy are single bombers. I think that trying new beers is essential to keeping me motivated to brew quality beer. Finally, there are a handful of breweries out there that produce such a good product that it would be a crime not to enjoy one every once in a while.