Este tutorial tiene una versión en español
Maybe you has a plain data plan with your cell carrier and this don't care to you, but in Cuba the data plans are expensive and we need to squeeze even the last byte of data from it
Some times you face this scenario: You connect your Cell Phone to the mobile data and set it up as a WiFi hostspot to share the internet with your work PC or Laptop; this is Ok, but then you have a dual waste of bandwidth; yes, think about it: