Please allow the HTTP headers "Cache-Control", "Expires", and "X-Cache*" type headers to be modified in API queries by utilizing the &maxage URL parameter, similar to action=raw's utilization. This would allow noncritical queries in user scripts, that perhaps activate on every page load, to not strain the servers overtly.
Inspiring example is a conceptual user status script that would query the API on every page load of participating users to check their last edit. By giving the query a squid-level and browser-level short cache, such as 15 minutes, the backend queries would be greatly reduced by the same user, or multiple users, visiting that user's page.
This parameter should probably be ignored for any write-function or anything sending POST data.