Password is one of the most important key to the security of money and it must be paid with good attention in the another case you could lose you money because of theft. I change my password each time when I feel that it is close to be opened.
Are you sure on what you're talking about ? In MyEtherWallet you don't need a password all you need to access your wallet is your private keys. You can't change it. Private key is the most important to secure your assets from there, if private key lost your funds will also lost.