How sound is it to confine oneself to saying "La ilaha illa Allah" (There is no god but Allah) three times after the Maghrib and Fajr prayers instead of ten times after Tasbih (Subhan Allah), Tahmid (Alhamdulillah), and Takbir (Allahu Akbar)?

The desirability of saying "La ilaha illa Allah wahdahu la sharika lah, lahu al-mulk, wa lahu al-hamd, wa huwa ala kulli shayin qadir. Allahumma la mani'a lima a'tayta, wa la mu'tiya lima mana'ta, wa la yanfa'u dha al-jaddi minka al-jadd" (There is no god but Allah, alone, without partner. To Him belongs sovereignty and to Him belongs all praise, and He is over all things competent. O Allah, there is none to withhold what You have given, and none to give what You have withheld, and no wealth or fortune can benefit one against You) after prayers is established. However, the addition of "three times" is weak due to the instability of its chain of narration and its contradiction of the reports from reliable narrators. It was not included by Al-Bukhari in its primary chapter.

Saying "La ilaha illa Allah..." ten times is not among the adhkar (remembrances) that are authentically established as Sunnah after Fajr and Maghrib prayers. Rather, it is among the adhkar of the day and night. Whoever recites it ten times in the morning or after Maghrib, ten good deeds will be recorded for him, ten evil deeds will be erased from him, ten ranks will be raised for him, it will be equivalent to freeing four slaves, and it will be a protection from Satan.