The same password may be used for different services, if the requirements defined for passwords by the services do not differ from each other.

The same password can easily be used in different services, as long as the password is sufficiently complex.

The same password can be used in different services, as long as it contains numbers and special characters in addition to upper and lower case letters.

The same password should not be used in different services: if your password falls into the hands of a third party, they can then log in to other services you use with the same password.