This is what Apple is training their Geniuses to tell people: It’s your fault. You’re using it wrong. Spend an entire day to reset the phone, install all of the apps again. Reconfigure them all. Place them all in folders and on home screens again. Kill your apps.
I don’t know why Apple hasn’t yet explicitly told all retail employees that “killing apps” in the multitasking tray is unnecessary, unlikely to solve any problem, and actually unlikely to have any effect at all due to the way iOS multitasks.
It’s one thing to hear this myth from the idiots at AT&T and Verizon stores, but it’s just embarrassing for Apple’s own retail employees to be peddling placebos that imply that iOS can’t multitask without constant babysitting and manual maintenance.