The first Ten Days of Dhul-Hijjah are the Best and Most Virtuous Days of the Year!
DOING GOOD DEEDS IN GENERAL: The first ten days of Dhul-Hijjah are the best and most virtuous days of the year. They are the days in which Allaah – the Mighty and Majestic – most loves the doing of good deeds. About this the Prophet (sallallaahu ’alayhi wa sallam) said, “The best days in the world are the ten days.” 
Imaam Ibnul-Qayyim (d.751H) – rahimahullaah – said, “Indeed, its days are the most excellent of all the days with Allaah.” And it has been confirmed in Saheehul-Bukhaaree (2/382), from Ibn ’Abbaas (radiyallaahu ‘anhumaa) who said, that Allaah’s Messenger (sallallaahu ’alayhi wa sallam) said: “There are no days during which good deeds are more beloved to Allaah than these (ten) days.” He was then asked, ‘Not even jihaad in the path of Allaah?’ So he replied, “Not even jihaad in the path of Allaah, except for a person who goes out with his self and his wealth, and comes back with nothing.” And it is these ten days that Allaah has taken an oath by in His Book, by His saying:
“By the Dawn and by the Ten Nights.” [Sooratul-Fajr 89:1-2]
This is why it is recommended to increase in making takbeer (saying Allaahu akbar), tahleel (saying Laa ilaaha illallaah) and tamheed (saying Alhamdulillaah) during these days …”
The Prophet (sallallaahu ’alayhi wa sallam) said, “There are no days that are greater with Allaah, and in which good deeds are more beloved to Him, than these ten days. So increase in making tasbeeh (saying Subhaanallaah), tamheed, tahleel and takbeer, during them.“ …