There are no doubt blessings and reward in calling salutations to the prophet SAW. However, amount of reward and thousands of days of good deeds and other virtues are not proven from authentic traditions or practices of the companions of the Prophet.
Please don't get me wrong, I am all in favor of sending salutations to Allah's Messenger as much as possible but only in obedience of Allah as He asked of us to do that. How he rewards us is best known to Him.
...and yet, he (SAW) himself stood in prayers for longest parts of the night and prostrated seeking forgiveness...his companions followed his footsteps in repentence...why did they not say this drood instead? I am confident that they did but after the prayers or in between prayers...
That makes me think that saying drood would wipe out sins that a human being commits unintentionally or those that may have happened between prayers.
Hadith of the prophet in Bukhari says that Allah SWT forgives sins of his servants that occured between one prayers and the next prayers, from one Friday to another Friday, and between one Ramadhan to the next.
