A security module manages differences in hygiene by applying differing levels of security policy to interactions of users with clients according to separate hygiene of the users and the clients. The module monitors computer security practices of clients and users in an environment, and uses this to client a machine hygiene score for a given client and a user hygiene score for a given user. The scores represent an assessment of the trustworthiness of the client and of the user. The module dynamically combines the scores computed for an interaction between the given user and given client, and applies a level of security policy to the interaction accordingly, determining what activities can be performed on the client based on the level of policy applied.