Q.What are the number of raka’aah (units of prayer) that a person does immediately after the jumu’aah prayer?
A.The shaykh (haafidhahullaah) said there is no specific limit that a person is obliged to pray or they should not go over. There is no specific limit. The Prophet (Sallahu alayhi wa sallam) prayed two and likewise he prayed four, so all of this is permissible. If a person prays in the masjid they can pray two and if the person prays at home they can pray four. But, if a person wishes to add/increase, if they want to pray eight or they want to pray ten in their home then it is permissible for them to do so.
You have the hadeeth of the Prophet (Sallaahu alahyi wa sallam) where he advised one of his companions (Umar ibn Abasa) when he questioned the Prophet (sallahu alayhi wa sallam) pertaining to the timings of the prayer. The Prophet (Sallaahu alayhi wa sallam) said, after Fajr do not pray until the sun has risen and then pray what you would like. Then after Dhuhr pray what you like. Then after Asr don’t pray until the sun has set. So the shaykh (haafidhahullaah) said so a person increasing in the amount of supererogatory prayers, there is no problem in them doing so. But that which is most beloved to Allaah (azza wa jall) is that which a person is consistent with, even if it be a small action.
Shaykh Saalih Muhammad al-Luhaydaan (May Allaah preserve him) (Kitaab-ut-Tawheed Class, Q&A Session 06-10-2012, Riyadh)