A timer has an interval set to occur more than once per second.

Do not poll more often than once per second or use timers that occur more frequently than once per second. Higher frequency periodic activity will keep the CPU busy and interfere with power-saving idle timers that turn off the display and hard disks.

Set timer intervals to occur less than once per second.

This rule should be excluded only if firing the timer more than once per second is required and mobility considerations can safely be ignored.