Would it be a good idea to sustain attention to the breathing sensation at the tip of the nose in everyday life?
Depends what everyday life is.
If you're kind of idle and have nothing to do,
If you're sitting down in the chair,
Yeah sure,
Go ahead.
However,
If you're walking,
Running,
If you're moving around,
It's meaningless to be aware of the breath.
And when you're moving,
The target of your mindfulness should not be the breath,
It should be your motions.
For example,
If you're eating food,
The fact that you're moving,
The motions of eating food should be the target of your awareness.
And when you're chewing,
The fact that you're chewing should be the target of your awareness.
And if you're conversing with someone,
Your eyes should focus on the other person's eyes,
And their facial movements,
And your ears should be focused on their voice.
If you're driving,
You should be focused on the driving and the situation all around.
Because if you're driving and you're focused on the breath,
Then obviously you're going to increase the likelihood of an accident.
So,
In everyday life,
Depending on situations,
Your mindfulness should be targeted towards the actual situation and the motions you exhibit.