Bought the Miata in '09, it had a OPTIMA YelowTop installed, and it did not look new. I never did check the date code, which is regrettable if only for the sake of the OP's question. But I replaced it in 2017 (8 years in my care) with another YellowTop, which (obviously) is working fine now.
I have had some conventional wet cell lead-acid batteries last six years, starting a tired chevy V8 in sometimes -40C winter weather. While working in the Arctic I once started it, from a field (no block heater) at -47C [-54F]. I had parked it there as the company truck was available to me and I had no intention of firing it up until the day I was scheduled to leave, in the spring. That's Mobil1 0W-40 and proper winter electrical maintenance at work. The truck had 220,000 miles but sometime before I got it it had a replacement motor (blue paint). No idea if it was a swap or a rebuild, but factory replacement GM 350's are black paint and chevy of course orange.
Used it to boost ["jump start" for the Americans reading] a 2006 F250, but even though I could get the Ford to turn over well, it never actually started. Had to drag it indoors and fire up some heaters.
I find that quite remarkable since I always bought conventional batteries with high Cold Cranking Amp capacity, which means the plates are closer together and more numerous than standard lead acids, and they are more susceptible to degradation as a result. As far as the ambient temperature goes, I knew it would start at -40C / -40F so it was a pleasant " cross your fingers" moment and it passed.
All my vehicles have spent extended periods of time in storage, so sitting for months at a time and starting right up is another requirement of mine.
I only use OPTIMA batteries now. Worth the extra cash to me.
