We'd use the last version of udev that doesn't need those, and if/when that becomes unsensible, look for alternatives.
The current situation is a bit similar, because the udev-to-systemd integration is not yet complete, so if I were to update udev right now, I'd have to use a tarball release from before the systemd integration.
It's looking a bit bad on that front, with both Lennart and Kay only caring about the systemd-integrated udev. There are some external contributors working on making the build-separate-udev-from-the-combined tree work as well as it did before, but I believe right now building only udev from the systemd tree wouldn't work fully.