Back in 2001 , when David Allen published the groundbreaking productivity book Getting Things Done , he coined the "two-minute rule": if you encounter a task that would take under two minutes to complete, just do it now. He wasn't recommending that you spend your days ricocheting between random little activities, the moment they pop into your head. His point was that anyone who takes a systematic approach to managing their time – with some combination of to-do lists, plans, schedules, and so on – inevitably incurs overheads. Those lists and plans take time and effort, and for some smaller tasks, it's simply not worth it. By the time you've "clarified the next action", or made an entry on a list, or scheduled a time to focus on it, you could have just done the thing.
Case in point: recently I realized I'd made three separate reminders to myself to order new bags for the vacuum cleaner. There's no way that didn't use up as much time and effort as just ordering the bags.