I asked Anas b. Malik about ablution. He replied: The Prophet ﷺ performed ablution for each prayer and we offered (many) prayers with the same ablution.  

كَانَ النَّبِيُّ ﷺ يَتَوَضَّأُ لِكُلِّ صَلاَةٍ وَكُنَّا نُصَلِّي الصَّلَوَاتِ بِوُضُوءٍ وَاحِدٍ  

The Prophet used to perform ablution for every prayer, but on the day of the conquest of Makkah, he performed all of the prayers with one ablution.  

أَنَّ النَّبِيَّ ﷺ كَانَ يَتَوَضَّأُ لِكُلِّ صَلاَةٍ فَلَمَّا كَانَ يَوْمُ فَتْحِ مَكَّةَ صَلَّى الصَّلَوَاتِ كُلَّهَا بِوُضُوءٍ وَاحِدٍ  

"The Messenger of Allah used to perform ablution for every prayer, and we used to perform all of the prayers with one ablution." (Using translation from Ibn Mājah 509)   

«كَانَ رَسُولُ اللَّهِ ﷺ يَتَوَضَّأُ لِكُلِّ صَلَاةٍ فَلَمَّا كَانَ يَوْمُ فَتْحِ مَكَّةَ صَلَّى الصَّلَوَاتِ كُلَّهَا بِوَضُوءٍ وَاحِدٍ»  

" كَانَ رَسُولُ اللهِ ﷺ يَتَوَضَّأُ لِكُلِّ صَلاَةٍ، فَلَمَّا كَانَ يَوْمُ الفَتْحِ صَلَّى الصَّلَوَاتِ كُلَّها بِوُضوءٍ وَاحِدٍ".