Since you mention Nietzsche, he had the following to say on precisely this topic in “Ecce Homo”:
“In my case all reading is among my recreations: consequently among those things which free me from myself, which allow me to saunter among strange sciences and souls – which I no longer take seriously. It is precisely reading which helps me to recover from my seriousness. At times when I am deeply sunk in work you will see no books around me: I would guard against letting anyone speak or even think in my vicinity. And that is what reading would mean … Has it really been noticed that in that state of profound tension to which pregnancy condemns the spirit and fundamentally the entire organism, any chance event, any kind of stimulus from without has too vehement an effect, ‘cuts’ too deeply? One has to avoid the chance event, the stimulus from without, as much as possible; a kind of self-walling-up is among the instinctual sagacities of spiritual pregnancy. Shall I allow a strange thought to climb secretly over the wall? – And that is what reading would mean … The times of work and fruitfulness are followed by the time of recreation: come hither, you pleasant, you witty, you clever books!”
Since you mention Nietzsche, he had the following to say on precisely this topic in “Ecce Homo”:
“In my case all reading is among my recreations: consequently among those things which free me from myself, which allow me to saunter among strange sciences and souls – which I no longer take seriously. It is precisely reading which helps me to recover from my seriousness. At times when I am deeply sunk in work you will see no books around me: I would guard against letting anyone speak or even think in my vicinity. And that is what reading would mean … Has it really been noticed that in that state of profound tension to which pregnancy condemns the spirit and fundamentally the entire organism, any chance event, any kind of stimulus from without has too vehement an effect, ‘cuts’ too deeply? One has to avoid the chance event, the stimulus from without, as much as possible; a kind of self-walling-up is among the instinctual sagacities of spiritual pregnancy. Shall I allow a strange thought to climb secretly over the wall? – And that is what reading would mean … The times of work and fruitfulness are followed by the time of recreation: come hither, you pleasant, you witty, you clever books!”