'54F100, 4 or 5 yrs. for chassis batteries is good. On our previous coach ('08 Dynasty), I got about 3 yrs. out of my 2 starting batteries which were maintenance free.
One thing that I hated, were the 8 wet-cell house batteries that I had to check the water in regularly. They would sulfate and I would clean them with baking soda, etc. I had to have the metal sliding trays painted twice in 7.5 yrs.
Finally, I bit the bullet and replaced the 8 wet-cell house batteries with 8 AGM's..... oh my gosh, pure heaven! No watering, no sulfating, no repainting the trays (after new batteries). As I recall, when getting the new AGM's, repairing the trays, installation and purchase of the batteries, tax, etc. was about $3,500. Worth every penny.
Good luck,
MM.