Not Just for Emergencies Anymore
Cellphones are becoming everyday convenience for older people, who once restricted their use of them to emergencies; half of Americans ages 65 to 74 own mobile phones, as do 30 percent of those 75 to 84; AARP is testing program that will provide its members with discounted calling plans and handsets from several carriers as well as material about how to use devices; carriers have been slow to market services to older Americans, even though older customers represent one of last remaining segments of population where there is potential for subscriber growth; photos; graph (M)