Intention > Attention
We only have a finite amount of attention that we can bring to focus at any one time, and although we can, like any other skill, grow our attention over time, knowing our current limits can help us to be more productive with our time.
Trying to do 2 or 3 complex tasks at once will overload our attention, whereas doing something simple or habitual alongside a single complex task yields far better results - walking a familiar route whilst concentrating on an audio book works well, but listening to that same audiobook whilst trying to hold a meaningful conversation will mean neither works out well.
Effectiveness, then, is all about being intentional about how we use our limited attention…