One of the core concepts of Getting Things Done is the two minute rule. It simply means that you should execute tasks that take less than two minutes to complete directly. The idea behind it is that it takes more time to write down, process the item into your system, schedule and do the task than it takes to complete and be done with it right away.
This simple change into your work can deliver great results in terms of what you get done and what tasks keep lingering on your todo list.
Personally it helps me to underestimate the time it takes to complete smaller tasks. Pick it up and measure. You’ll be surprised what you can do in two minutes.