Every heart --good or bad, soft or hard, selfless or selfish, loving or hating, humble or proud-- can stand for salah and recite the Koran.
But ONLY a NOBLE heart can bless another. ONLY a NOBLE soul can bless another. Only a NOBLE person can send/invoke blessings on the Prophet(sallallahu alaihi wasallam).
Durood is not released easily from a hard, bad, wicked or a selfish heart . Only a noble heart is able to release the blessing easily.
And vice versa, if you are bad , but you force yourself to recite durood, then inturn, it ennobles you. It ennobles your heart as well as your mind. It ennobles your thought. It makes your thinking noble. That is why the gnostics ( the ones who know God and who are the best of the learned among us today) always stress on durood. And it is for the same reason that the Prophet (sallallahu alaihi wasallam) also stressed so much on durood after Salah and Koran.
If you are one who offers salah and recites the Koran respectfully, then it should direct you / guide you towards durood. And if you are one who simply recites durood, it will direct you / guide you towards salah and Koran and noble thinking.
Salah, Koran, all the books of Hadeeth AND DUROOD. These are the four things the person belonging to the right sect believes in. If he or she thinks even one of them is unnecessary or less important , then he or she cannot belong to the right sect.
If you are of the right sect, then you have to be of Noble thought. Think right and think noble in everything. That was the Prophet's (sallallahu alaihi wasallam) thinking.
DUROOD PROTECTS YOUR THOUGHTS :
When you send blessings on the Prophet(pbuh), your own thoughts are protected from the Devil. But when you don't send blessings on the Prophet, then your thoughts are no longer protected and you end up misinterpreting things even from the most guided source as the Qur'an. That is why always send blessings on the Prophet(sallallahu alaihi wasallam) before and after you read or recite the Koran so that you are not misguided and don't misinterpret things in it.
As such Durood can be sent up on the Prophet(sallallahu alaihi wasallam) anytime during day and night everyday.............but here are some times in your everyday life when you should essentially send durood on the Prophet so you are guided better:
Send blessings on the Prophet(pbuh) in your 5 prayers everyday. (after you say the shahadah. Its the correct sunni way. )
Send blessings on the Prophet(sallallahu alaihi wasallam) before and after you recite or read or ponder over the Koran.
Send blessings on the Prophet(sallallahu alaihi wasallam) before and after you read any Koranic tafseers or hadeeth books. It will keep your thoughts guided as you read and help you arrive at the right conclusions and the right understandings.
When you offer your 5 prayers everyday and recite Surat al Fatiha in it seeking guidance, Allah either guides you towards a source of knowledge like the Koran or hadeeth or other books or ppl............ , or directs a source towards you. But how much guidance you actually pick up from that source depends on how much blessings you send on the Prophet(pbuh). Invoke any blessing you like, but invoke blessings on him.
Send blessings on the Prophet(sallallahu alaihi wasallam) whenever your thoughts are confused or unclear in any matter in life. Durood will guide your thoughts in that matter.
Send blessings on the Prophet(sallallahu alaihi wasallam) when you research over, or read about any matter in religion or worldly sciences. It will guide your thoughts as you read or ponder and help you understand it correctly.
Ur child is poor in any subject in school? Finds that he cannot understand it? Tuition teacher is fine. But just teach him to send up a little blessing on the Prophet(sallallahu alaihi wasallam) every time he sits down to read that subject and then notice the difference. He will be able to understand things by himself as his thoughts will be guided correctly.
Send blessings on the Prophet(sallallahu alaihi wasallam) before and after you make dua. Prayers sealed with durood are essentially accepted.
Send blessings on the Prophet(sallallahu alaihi wasallam) every time you are sick. Send blessings on the Prophet(sallallahu alaihi wasallam) every time you are in difficulty. Salah you offer anyway and also make dua. But this time also send blessings on the Prophet(sallallahu alaihi wasallam) and notice the difference how you are guided out of your difficulty.
The one thing that separates the right sect from all the others is the invoking of the blessings on the Prophet(sallallahu alaihi wasallam). So send salaat on the Prophet(sallallahu alaihi wasallam) abundantly.