I realize that I'm fighting the tide, but I'm going to ask anyway: please don't do this very often. And when you do, please have basic respect for other people, purchase from the business frequently (every hour or so, at minimum), limit your total seat time to an hour if the place is crowded, and don't be "that guy" -- the dude spread over two tables, with the laptop stand, the iPad, the backup drive, the portable keyboard, mouse, etc.

There's nothing worse than walking into an otherwise pleasant cafe and being unable to sit because the place is filled with laptop zombies and/or dudes (and it's always dudes) holding "business" meetings. In San Francisco and Seattle, there are dozens of cheap co-working facilities, but you still can't get a seat to eat lunch in a place like Coffee Bar or the Creamery for all of the nerds that crowd in between 9AM and 5PM.

Finally, if you find yourself working at a cafe for eight hours a day, every day, you're abusing the system. Go to a co-working facility, and pay the minimal amount of money for a desk. If you can afford paying for multiple coffees every day, you can afford a co-working space. If you can't afford either, you should work at home, or in a library. The coffee shop is not your personal, low-rent office space.