Isolate and Duplicate

A large part of troubleshooting can be summarized by two words: isolate and duplicate.

Can we make it do whatever it did the last time when it didn't work right--again? And again? (duplicate.)

And under what conditions? What about when we're not doing the "happy path" or normal use case and are on this particular variance? In other words, does your engine light come on all the time or just when you're at a stop light? Or even better, when you're at a stop light in 95 degree heat, etc. (isolate.)

We could all save ourselves and the growing number of technical support staff we must appeal to on a regular basis to get through our day-to-day lives if we try to do these two things before we make our appeal.