Why should encryption key be rotated after it has been used to encrypt a specific amount of data?

I’m going through OWASP Cryptographic Storage Cheat Sheet and it says:

Encryption keys should be changed (or rotated) based on a number of different criteria: (…) After the key has been used to encrypt a specific amount of data. This wo… Continue reading Why should encryption key be rotated after it has been used to encrypt a specific amount of data?