Does Allah accept repentance immediately if the conditions for repentance are met, or after a long period?

Whoever repents with sincere repentance, Allah will accept his repentance. There is no text that specifies the duration for Allah Almighty to respond to those who repent. The acceptance of repentance might be delayed for some disobedient individuals, as happened with the three companions who lagged behind the Battle of Tabuk. Their repentance was deferred due to a divine wisdom, or because they did not overdo their apologies. They remained awaiting Allah's command for fifty nights until their repentance was revealed in the Holy Quran.