Hopped in the RX-7 this morning to go out for a drive and pick up some stuff from Summit. After it started up, I noticed the volt gauge (something missing on new cars, like all the other useful gauges...) was reading lower than it usually does, like as low as “it isn’t running” is.

A quick check with the nearest multimeter confirmed that it is not charging. I revved the engine some, and even banged on the alternator with a rubber mallet to no avail (yes I checked the wiring, it’s still there), so I’ll be ordering a new (well, reman) one today.
The lesson here: gauges are important and you should look at them. Otherwise, you might get halfway to Summit before you realize the battery isn’t charging and the car dies along the highway, instead of still-in-the-garage.