It is a nice topic though it is now common to everyone.using the same password for multiple accounts is very risky and most internet pages now, if you enter a password or an email that is already used somewhere else you will be notified.
The Idea of having an password manager is also risky it is not wise to entrust your personal password to someone rather you can write it down in a paper and look for a safe place to keep it keeping it with a person will be very easy to break into your account humans these days are not to be trusted especially when it happens to be finances.
Actually it's not bad to use one password to secure all your datailes, as long as your password doesn't contains your name or any dictionary words it's secured. A password is what we shouldn't try to forget, because there are something that do not permits resetting of password because of their security reasons, and it's stated there when you are setting the password.
It's not also good to be changing passwords all the times, there there are people who always change passwords or uses different passwords to secure their account but surprisingly don't know how they managed to forget their password. Password is a thing that supposed to be installed in every ones brain because it's not like seed phrase, it's something that you setup by your self.