battery question

Pretty interesting threads.  The only time I charge my 2 12v deep cycle marine batteries is when I put the pod away in our horse barn  mid-late October and then when I bring it out of hibernation in April.  When I charge I will use the 2 amp trickle charge for about 1 day/battery.  When dry camping I will take the battery down to 1/3 of full charge before changing over to the other battery.  We are now into year 6 on our original batteries, still appear to have a lot of life left in them.  Also check the battery fluid levels a couple times a year as well, using only distilled water, no well or city water.