And, on the other side of the coin, and I may be learning something here, but when I had my 3 Interstate 27's (all but one was 4-5 years old) replaced over a year ago with 3 29's, (one had bad cell), the mechanic (40 years experience) used the year old 27 (after complete testing) for the chassic battery. He said it would work just fine and was better than the one that was in there. I THINK the old chassic battery was an Interstate 800 CCA and it was about 5 years old. Actually still have it in the shop for 12v testing.
So, that's my story. All works well, no problems.
2002 W-22 266"wb, Winnebago Chieftain 39T, UltraPower, Koni's, Helwig bars, Nuvi 660, Sirius, Scan Gauge II, Sentry TM. 2003 LW300 Saturn toad, Sterling towbar & Apollo brake. And Hannah the Princess and Stevie the Dude!