AGM battery questions

My yellowtop has been going strong for 14plus years. Starts the car every spring after being stored outside in the trunk, at up to -35*C.
Its been;overcharged, under charged, and drained to near death. It doesnt outgas, leak, corrode, or talk back to me. Its never cost me a tow-call, or left me stranded anywhere.Its seen at least two alternators, and three regulators.Stone-age reliable
Its been flat-out the cheapest battery I have ever owned.