All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
There is no doubt that time is of great importance in Islam and it has a special importance in the life of a Muslim as it is in reality the life and age of a person. If time is lost, subsequently the life of a person is lost. In His Book, Allaah made clear the importance of time as He swore by some parts of time in verses like Al-Fajr, Al-Asr, Al-Layl, Al-Nahaar. The Prophet 
  drew our attention to the importance of time as he said: "People are losers in respect of two bounties, i.e. health and free time" [Al-Bukhari]. Moreover, the first thing that a person will be questioned about on the Day of Judgment is his time (and his age). The Prophet 
  said: "The son of Adam will remain standing on the Day of Judgment till he is questioned about five things: his age, how he spent it; his youth as to how he consumed it; his wealth from where he acquired it and in how he spent it, and about his knowledge and how he utilized it". [At-Tirmithi]
As regards to how a Muslim should organize his time, it should be spent in performing obligatory and supererogatory acts of worship, seeking one's sustenance, acquiring knowledge, attending circles held by scholars, and not sleeping too much. There is no harm to entertain oneself sometimes in what is permissible without being extravagant. One should not sleep after Fajr, as the Prophet 
  and his companions used to mention Allaah after Fajr prayer until sunrise. Jabbir 
  said: "The Prophet 
  used to remain sitting in his position where he prayed Fajr until sunrise. When the sun rises, he would get up." [Muslim]
The Prophet 
  also said: "O, Allaah! bless my nation in its early times." [Abu Daawood, At-Tirmithi, and Ibn Maajah] He specified early times – which is the early part of the day-with the mention of Allaah, as this time of the day is a time of being active. It is reported that Az-Zubayr Ibn Al-'Awwaam 
  used to forbid his children from sleeping in the morning. 'Urwah, the son of Zubayr 
 both, said: "Indeed I hear people sleeping in the morning, and I abstain from it". [Ibn Abu Shaybah]
Regarding sleeping after 'Asr, this is something disliked by a group of our righteous predecessors 
  however, we do not know any sound evidence from the Prophet 
  or his companions 
  about this time being disliked. So there is no harm to sleep, if a person is in need to sleep during this time, as in principle it is permissible. 
Allaah knows best.