When it comes to smartphone upgrades, there are three different types of people. There are those who can't wait to get their hands on any new model their brand of choice churns out. There are those who upgrade their device whenever their contract is up for renewal and there are those who stick to their device until it no longer works or becomes totally obsolete.According to the somewhat surprising results of a Gallup survey among 15,000+ U.S. smartphone users, the majority belongs to the latter group. 54 percent of smartphone owners stated to stick it out with their device until the bitter end, while only 2 percent of the respondents admitted to purchasing a new phone whenever a new model arrives.Interestingly, iPhone users tend to upgrade their phones more frequently than those using Android devices. While 51 percent of Apple devotees usually upgrade to a new model as soon as their provider allows it, the majority of Android users patiently wait for their phones to bite the dust before splashing out for a new device.