They don't fail per-se, unless of course a bug is found.

I also add new functionality relatively frequently to a base API wrapper that is needed by multiple other distributions. To ship the new functionality out, it's nice to run one command to let me know which other dists are at which, so I know whether they need to be updated to use said new functionality or not.

It gets more complex when these modules can be brought in by one distribution, or used individually. If for instance the API wrapper module gets added to it a new feature for I2C, obviously I want the I2C distribution that uses that to be updated. I may have also made changes to a part of the SPI code or whatever. Listing out what modules are behind is a good way to understand what is what.

My interfaces are definitely very consistent; I wrote this software to inform me of where I may be lagging behind, and which modules would benefit from a prereq bump. Combined with my auto CI software that tests *all* reverse dependencies of each module (mine and others), I can 100% ensure that external authors' dists will continue to work as well as my own. If my tests fail, I review everything as to what broke, why it broke, and take corrective action.

In this way, I am certain that I haven't broke other modules of mine, other modules of others, and modules of others who use the others (or my) distributions.

It's a pretty sure fire way to ensure the whole CPAN river stays sane.

Curious... do you have any knowledge of other Perl authors who test the whole river each time they go to make a new release?