All phones are out of date after, say, half a year. So, if you have a 2-year contract, you're out of date one and a half year (75% of the time). With an iPhone it's somewhat better, because Apple has a new one each year. So they take one year to be hopelessly outdated.
Buying a new unlocked unsubsidized phone and selling it on eBay half a year later is the only solution to stay up-to-date.
With all the new cell phones coming out in 2012, should I wait to see what is offered in the next releases or is there a "must have" cell phone out there right now? I currently am due for an upgrade but don't like the idea of being locked in to a phone that is going to be out of date soon.