In a letter to U.S. senators Amazon said it keeps your Alexa voice recordings indefinitely unless you manually delete them.
In the letter to Coons, Amazon noted that for Alexa requests that involve a transaction, like ordering a pizza or hailing a rideshare, Amazon and the skill’s developers can keep a record of that transaction. That means that there’s a record of nearly every purchase you make on Amazon’s Alexa, which can be considered personal information.
Check It Out: Amazon Alexa Voice Recordings are Stored Indefinitely