Observation of information workers reveals that they switch. tasks on average every three minutes [12]. Much switching. concerns email: studies show with consistency that people. spend about 23% of their time on email [8, 25], with an. estimate that people check email about 36 times an hour. [25]. This could be an overestimation, but even if halved, and if true, it would comprise a large component of. multitasking.