Just 12 months. The original battery lasted about 5 years.
Check the battery terminals (for corrosion) and the wiring connectors at the terminals. Odds are they're the primary culprit in this.
From the Oh Good Grief department: the negative terminal has some white gunk, and the negative cable is completely loose! It looks like the dealer (the last shop to do work that would require disconnecting the battery) totally forgot to actually tighten the clamp. I could lift it off with my little finger. Unfortunately I didn't have a suitable wrench or terminal cleaning tool when checking this last night, so I'll fix this later today.
However, I wonder if that's the real problem. Though loose, the clamp did seem to make good contact and hadn't actually wiggled off the post. But under engine vibration maybe it does cut in and out.
With zero experience in this area, I'd have thought a flaky battery connection would cause more dire problems like lights and other major systems simply cutting out, rather than my elusive dashboard "gremlin" symptoms. However I'll clean and tighten it tonight and report back.
