I really don't think theres an accurate answer to this
But the answers to this question depends on alot of stuff.
Hey buddy say u had a marine battery with a yellow top optima and they are brand new, u already know the yellow top optima battery is gonna last longer. To tell you the truth it all depends on the voltage your running on your setup and how long u hit your switches and a couple of other thing, sorry if i couldn't give you a straight forward answer
the only info I found is if you charge your batterys all day then you take the top charge off the batts (hook up a light for a min.) then check the volts if it's around 12.9/12.8 the battery is like new at 12.5 it's still doing fine and at 12.2/12.1 theres not much life left in the battery........this is only to get and IDEA of how good your batterys are