The Prophet ﷺ said: ʿWere it not that it would be too difficult for the ummah, I would have commanded them to use the siwak at the time of every prayer.” (Using translation from Aḥmad 607)

أَنَّ النَّبِيَّ ﷺ قَالَ «لَوْلَا أَنْ أَشُقَّ عَلَى أُمَّتِي لَأَمَرْتُهُمْ مَعَ الْوُضُوءِ بِالسِّوَاكِ عِنْدَ كُلِّ صَلَاةٍ»