Abstract: Methods and apparatus for dynamic content customization provided to clients. When a profile repository is used to store profiles indicating typical device characteristics for various clients, the repository is configured to allow a stored profile to be flagged to indicate a client is capable of being queried for dynamically determined changes and/or additions to its stored profile. Communication between content providers, e.g., one or more servers, and the client may be configured so a minimum number of notifications need be made by the client to the servers to indicate the client can be queried for specific dynamic characteristics or deviations from a default profile (if any).