Never. On the other hand, I have considerable confidence that I could do so, and that if something goes wrong with upstream development, someone is likely to do

Never. On the other hand, I have considerable confidence that I could do so, and that if something goes wrong with upstream development, someone is likely to do so. If I use a free-binary-but-no-source product, I’m much more likely to get stuck. (Of course, as a regretful MySQL user, I am pretty stuck, but largely because MySQL is, in many respects, a terrible product. It does, quite reliably, get security updates at the kind of general maintenance that keeps it working no worse than it ever did.)