A lot, see that yet another recent study: http://www.talentsmart.com/articles/Multitasking-Damages-Your-Brain-and-Your-Career,-New-Studies-Suggest-2102500909-p-

A lot, see that yet another recent study: http://www.talentsmart.com/articles/Multitasking-Damages-Your-Brain-and-Your-Career,-New-Studies-Suggest-2102500909-p-1.html http://www.talentsmart.com/articles/Multitasking-Damages-You... I use an Android phone that lasts consistently more than 2 days (Sony z3 compact). Of course I don't have Facebook installed...