I will do the work for them (typically paid for by my employer) iff I can expect them to fix it.

Blackbox debugging is a PITA, which is part of why I prefer open source, but it is what it is... If something is broken, and I can get it fixed by putting in the time to get a good report, and etc and they fix the thing, then I'll do it.

But if they don't fix the stuff, I have no shortage of things to fix myself.