Even Though the Nights Have Become Longer, However a Student of Knowledge Should Avoid Excess Sleep
The student of knowledge should sleep less as long as it does not harm his body and mind. He should not sleep more than eight hours in a day and night, which is a third of one’s time within a twenty four hour period. However, if he is able to sleep less, he should do so.
[Source: (تذكرة السامع والمتكلم – page 77) & quoted by Shaikh Raslaan (may Allaah preserve him) in Fad’lul Ilm’ page 281]