Is it obligatory for the worshiper to say the Tasbeeh during bowing (Ruku') or prostration (Sujud) the same number of times they are accustomed to (five times or more) in each Ruku' or Sujud, whether praying alone or behind an Imam? And what should one do if they doubt the number of Tasbeehat or Istighfar in the morning and evening remembrances (adhkar), and should they repeat the dhikr anew?

Reciting "Subhan Allah" (Tasbih) during bowing (rukūʿ) and prostration (sujūd) is sufficient even once, and there is no specific number mandated for it. The minimum for perfection is three recitations, and it is permissible to recite more than that. The matter is broad. If a worshiper recites "Subhan Allah" five times, they are not obligated to adhere to this number in the remaining prayer units (rakʿahs); rather, they may increase or decrease it. The majority of scholars hold the view that reciting "Subhan Allah" during bowing and prostration is a Sunnah (recommended act) and not obligatory. If there is doubt about the number of recitations, there is no harm in restarting the count from the beginning. It is permissible to use prayer beads (misbahah) to keep track of the number, though it is preferable to use the fingers whenever possible.