I think this is indeed something that isn't very "compatible" with the regular way of distribution packaging.
For Gentoo however, it's simply checking if dependencies have changed and if so, test for dependency hell or if certain dep versions are not stable yet. And check if there has been some low-level change requiring the way the program compiles or installs et cetera.If there's no issue with the deps, you can simply bump the version number. Easy peasy.
Gentoo has its drawbacks, but for getting cutting edge versions of your software, it's great!