Assalam alaikum, In Ayat 16 of Surat Sajdah of the Holy Qur'an (32:16), Allah Subhanahu Wa Ta'ala says:-- "THEIR SIDES FORSAKE THEIR BEDS." With this Ayat, Allah Ta'ala has legislated qiyamul-layl all year-round and made it a sign of the righteous. Whoever has the strength to pray the Tahajjud, he should do so in the last part of the night, otherwise one should pray witr before going to sleep. Du'a/Supplication is the most apparent and easiest form of 'Ubudiyyah [enslavement]. The Prophet, peace be upon him, said, "Du'a is worship". It is also impermissible to abandon Du'a. The Prophet, Sallallahu alaihi Wasallam, said, "Whoever does not ask Allah He becomes angry with him." So, we nust accustom our heart and hands to supplicating to Allah Ta'ala always.