For how long should Qunoot during prayers be said at times of calamity?
Question

                Some imams say Qunoot for one or two days at times of calamity then they stop. For how long should du’aa’ be offered at times of calamity?.
Praise be to Allah.
    Saying Qunoot in the obligatory prayers is prescribed when 
    there is a reason for that -- which is when calamity is befalling the 
    Muslims. So long as calamity is occurring, then Qunoot should be said for 
    that, and when the reason is no longer present, then Qunoot should stop, 
    because the Prophet (blessings and peace of Allaah be upon him) continued to 
    pray Qunoot against the mushrikeen and to pray for the oppressed Muslims in 
    Makkah for a month, then he stopped saying Qunoot when the reason for it 
    stopped with the arrival of those for whom he had prayed Qunoot. This is 
    indicated by the hadeeth of Abu Hurayrah (may Allaah be pleased with him) 
    according to which the Prophet (blessings of Allaah be upon him) prayed 
    Qunoot for a month. After saying Sami’a Allaahu liman hamidah, he said in 
    his Qunoot: “O Allaah, save al-Waleed ibn al-Waleed, Salamah ibn Hishaam, 
    ‘Ayyaash ibn Abi Rabee’ah and the weak and oppressed believers. O Allaah, 
    punish Mudar severely and send upon them a famine like that of Yoosuf.” Then 
    Abu Hurayrah (the Allaah be pleased with him) said that they were saved from 
    the clutches of the kuffaar and came to Madeenah, so the Messenger 
    (blessings and peace of Allaah be upon him) stopped praying for them. 
    Narrated by Muslim (675). 

    Ibn al-Qayyim said: He prayed Qunoot at the time of calamity 
    to offer supplication for some people and to pray against others, then he 
    stopped when those for whom he had prayed came (to Madeenah) and were saved 
    from captivity, and those against whom he had prayed became Muslim and came 
    repenting. So his Qunoot was for a purpose, and when that was achieved he 
    stopped Qunoot. End quote. 

    Zaad al-Ma’aad (1/272) 

    If the calamity is still ongoing and has not ceased, such as 
    the occupation of Iraq for example, or the occupation of Palestine, then 
    Shaykh Ibn ‘Uthaymeen (may Allaah have mercy on him) stated that in this 
    case it may be said that Qunoot may be offered for a month and then 
    stopped. 

    And Allaah knows best.