Hadithcore
Mishkat al-Masabih, 425

Anas said that God’s messenger used to perform ablution for every prayer, but that they made the ablution serve as long as they did nothing which broke the state of ceremonial purity. Darimi transmitted it.

وَعَنْ أَنَسٍ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَتَوَضَّأُ لِكُلِّ صَلَاةٍ وَكَانَ أَحَدُنَا يَكْفِيهِ الْوُضُوءُ مَا لَمْ يُحْدِثْ. رَوَاهُ الدِّرَامِي

References1 variant
In-Book Reference
Book 3, Hadith 130