Are there best practices concerning application account credentials

I am looking for best practices concerning application account credentials.

For example, suppose I got a corporate application which uses an Active Directory application user account to communicate with corporate LDAP. Then, what is the best way to manage this account and its credentials (client-side) ?

Is it needed to encrypt a configuration file with these credentials, with an administrator decrypting it (Password based encryption) when application starts ? It seems the best way but it is not very easy to update LDAP account password because you need to modify and re-encrypt the configuration file.