A method is described of using the mobile device so as to control the drain of power from the power source of the mobile device, the mobile device having at least two location determination techniques having respective power drain characteristics, the method includes selecting the location determination technique having a lower power drain characteristic the greater the determined distance of the mobile device from a predetermined location or area, and selecting the location determination technique having the greater power drain characteristic the smaller the determined distance of the mobile device from a predetermined location or area. The method thus uses the least accurate technique when furthest away and the most accurate technique when closer to a predetermined location or area.