You open your to-do app. It has 213 tasks. Just looking at it is exhausting, so you close it and do something else. The hardest part of a 40 item to-do list isn't doing the tasks, it's deciding which one to start.
Focus5 keeps the whole list like other apps but hands you five at a time, one on screen with the timer already running. So you just focus on that one task only. Once you complete it, focus on the next one.
No more deciding what to do next. Just focus on the five, that's it.