Sayyiduna Abu Umaamah (radhiyallahu ‘anhu) reports that Rasulullah (sallallahu ‘alaihi wasallam) said, “The one who recites Aayatul Kursi after every fardh salaah, nothing will prevent him from entering Jannah besides passing away.” (As Sunanul Kubra - Nasai #9848)
The recitation of Aayatul Kursi is extremely easy as it will take perhaps only half a minute and can thus be recited comfortably after every salaah. The benefit of reciting Aayatul Kursi after every salaah is that after passing away, the reciter will be admitted into Jannah extremely swiftly.
It should be understood that the benefit of reciting Aayatul Kursi after every salaah and other actions of this nature, which promise to bring a person certain benefits, will only be enjoyed if there are no ‘obstacles’ in a person’s life. Hence, if a person carries out this action, but also continues to commit sins and does not repent, then these sins can be an obstacle that will delay his admittance into Jannah.
Since the one who recites Aayatul Kursi gains the protection of Allah Ta‘ala, reciting it after every salaah will prove very beneficial for those who suffer from sihr (black magic) and will also provide protection from robberies and other dangers. However, when reciting Aayatul Kursi, we should not do so in parrot fashion with a negligent heart. Rather, we should turn our hearts to Allah Ta‘ala with the conviction that we are begging Allah Ta‘ala to protect us and grant us speedy entrance into Jannah.
May Allah Ta‘ala assist us all to recite Aayatul Kursi after every fardh salaah, aameen.