Well, after 23 years of daily use, my trusty Battery Tender (1.25A) has finally died. That was a good run. Unfortunately, the bike it's been plugged into now has a discharged battery. We'll see if one of my spare Battery Tender Jr.'s (0.75A) can revive it.
Bummer. It, as you say, it was a good run indeed.
My BT is about the same age. I bought it as soon as it came on the market and is still going strong.
However, I now have an Optimate 3 that I'm using the most these days because if it's desulfating feature.
I could not find anything on the Battery Tender Jr., nor my Yuasa PowerShot to support use with an AGM battery. So, for Christmas, my daughter gave me a Battery Tender Plus, which will charge AGM properly. (All my cycles have AGM batteries.) I bought another cycle recently which had a one year old PC680 in it and the PO said he kept it on a trickle charger. I could never read more than 12.6 V. Therefore, the battery would barely turn the starter, thus the ABS voltage test at start up failed (BMW R1100RT), so I replaced the PC680 with a MotoBatt which came pre-charged at 12.8 V. Turns out the starter was drawing too many amps so I replaced it. All is well now. I did the deep discharge/recharge thing on the PC680 about 6 times and now, the battery is holding steady at 12.7 V, just sitting on my workbench.