Use only individual accounts and never share passwords
User accounts and their corresponding unique passwords need to remain strictly confidential to guarantee security. Shared accounts carry a risk of diluting responsibility as it makes it very difficult to allocate operations performed by that account to an individual.
Assigning accounts to single individuals, i.e. not using (shared) generic accounts creates user accountability. One user can have several accounts for several levels of access, but each of these accounts is strictly personal.