It seems some consumers are starting to feel upgrade *fatigue. A report by Recon Analytics, a US-based market research firm, found that people in some countries were waiting longer to buy new mobile phones. US citizens change their phones the most often around the world. In 2007, people in the US upgraded their phones every 18.7 months on average; three years later, this number had *stretched to 21.1 months. Contrary to developed countries, people in emerging economies replace their gadgets more often.