Is there a phone whose battery lasts (in stand-by mode) up to 15 years ? If you are willing to use less multimedia applications and to limit your calling time, then yes!
Battery for 15 years!
SpareOne is the first mobile phone that works with one AA battery - one of the most popular and readily available batteries. It provides up to 10 talk hours and 15 years of standby mode - so, in case of an emergency, the phone can be always used.
With a reasonable price ($50 on U.S. market, the producing will begin on March 2012), without display, this is a very simple device, that works with any SIM card in GSM 850/1900 MHz or 900/1800 MHz and can be kept as a "backup phone" for cases where the your smartphone is discharged!
The phone offers a reachable dedicated emergency number (hold down for two seconds) and 3-button setup option to speed dial. This one seems like Back To The Future!
Read Space 3 Concept Phone