A fellow coder was looking for a fix to a problem I’d never considered; how do you change the update frequency for the RSS feed on a Joomla -driven site? I had no idea, but that’s why we have Google and the Open Source model that almost guarantees that a funky developer somewhere out there has cranked out a widget to solve the problem you didn’t even know you had.
And so, we find this site, which in turn recommends this. That last one is in German, but the module they’re using is in English. Top-and-center is the parameter you need to mess with; set the cache time as low as you need it, and the RSS feed will be updated as required.