Imaam Ahmad (rahimahullaah) said:

”I never wrote down a hadeeth except that I acted on it at least once, so that it may not be a proof against me.”

[Quoted by: Shaikh Jamaal al-Fareehaan al-Haarithee in Ad-Durar Al-Manthoor Minal Qawl Al-Ma’thoor: page: 34.  The Shaikh referenced the original source of this statement of Imaam Ahmad to Adabul Imlaa Wal-Istimlaa (323), Manaaqib Ahmad (179) and other sources]